Activation energy of field emission flicker noise power due to adsorbed potassium on tungsten

The temperature dependence of the field emission flicker noise spectral density functions has been investigated for potassium adsorbed on tungsten (112) planes by a probe hole technique. By integration of the spectral density functions $\text{W(?) = B}{}_{\mathrm{i}}\text{?}{}^{\mathrm{?ge}}\text{i}$ the noise power $\text{(δn}{}^2{}_{\mathrm{\Delta ?}}$ for different frequency intervals Δ? is obtained. From the exponential temperature dependence of $\text{(δn}{}^2{}_{\mathrm{\Delta ?}}$ noise power “activation energies” q_Δ? are determined. Plots of these energies versus coverage show a similar “oscillating” behaviour as recently found for $\text{W(?}{}_{\mathrm{j}}\text{)}$ or which indicates phase transitions of the adsorbed potassium submonolayers. The noise activation energies are discussed in terms of existing models and a comparison is made between the experimental q values and surface diffusion energies E_d as determined by conventional methods.     

Two theorems on the level order in potential models

We study the potentials of the form U(r)=?r^?1+λV(r), $\text{(}\text{d}\text{d}\text{r}\text{)(}\text{r}{}^2\text{d}\text{V}\text{d}\text{r}\text{)?0}$, and show that the energy levels satisfy the inequalities $\text{E(N}{}_{\mathrm{c}}\text{, l)?E(N}{}_{\mathrm{c}}\text{, l+1)}$ to first order in λ, where N_c denotes the coulombic principal quantum number and l the angular momentum. Similarly for potentials $\text{U(r)=r}{}^2\text{+λV(r), (}\text{d}\text{d}\text{r}{}^2\text{)}{}^2\text{V(r)?0}$, we prove to first order in λ that $\text{E}\text{?}\text{(N}{}_{\mathrm{H}}\text{,}\text{l}\text{)?}\text{E}\text{?}\text{(N}{}_{\mathrm{H}}\text{,}\text{l}\text{+2)}$, where NH denotes the harmonic oscillator quantum number. In the latter case, we give also quantitative restrictions on the relative positions at the lth and (l+1)th states.     

Gravitational collapse in quantum mechanics with relativistic kinetic energy

It is proved that the quantum mechanical Hamiltonian $\text{H = Σ}{}_{\mathrm{i=1}}{}^{\mathrm{N}}\text{(p}{}^2\text{+ m}{}^2\text{)}{}^{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}\text{? κ Σ}{}_{\mathrm{i>j}}\text{|x}{}_{\mathrm{i}}\text{? x}{}_{\mathrm{j}}\text{|}{}^{\mathrm{?1}}$ for bosons (resp, fermions) is bounded from below if N ≤ c_bκ^?1 (resp. $\text{N ≤ c}{}_{\mathrm{f}}\text{κ}{}^{\mathrm{<mtext>?3</mtext><mtext>2</mtext>}}$). H is unbounded from below if N ≥ c_b^lκ^?1 (resp. $\text{N ≥ c}{}_{\mathrm{f}}{}^{\mathrm{l}}\text{κ}{}^{\mathrm{<mtext>?3</mtext><mtext>2</mtext>}}$). The constants c_b and c_b^l (resp. c_f and c_f^l) differ by about a factor 2 (resp. 4).     

Conductivity of a quasi-one-dimensional metal at finite temperatures

The longitudinal conductivity of a quasi-one-dimensional metal is calculated for the case T?ω_D (ω_D being the limiting phonon frequency) and ω_Dl¹/v?1 where l¹ is the effective mean free path determined by impurity and phonon scattering: $\text{l}{}^1\text{= (l}{}^{\mathrm{?1}}{}_{\mathrm{ph}}\text{+ l}{}^{\mathrm{?1}}{}_{\mathrm{i}}\text{)}{}^{\mathrm{?1}}\text{, l}{}_{\mathrm{ph}}\text{= v/λT, l}{}_{\mathrm{i}}$ is the impurity mean free path. The conductivity is σ = (c₁e²/πS)l³_iv^?2ω_DλT for l_i?l_ph, σ = (c₂e²/πS)vω_D(λT)^?2 for l_i?l_ph, λ being the dimensionless electron-phonon interaction constant, c₁, c₂ ～ 1, S = a_xa_y is the (xy) area per one chain.     

Global aspect of steady-states for competitive-diffusive systems with homogeneous Dirichlet conditions

This paper is concerned with the competitive-diffusive systems

$\text{u}{}_{\mathrm{t}}\text{=d}{}_{\mathrm{l}}\text{u}{}_{\mathrm{xx}}\text{+(a}{}_{\mathrm{l}}\text{?b}{}_{\mathrm{l}}\text{u?c}{}_{\mathrm{l}}\text{v)u}\text{v}{}_{\mathrm{t}}\text{=d}{}_2\text{v}{}_{\mathrm{xx}}\text{+(a}{}_2\text{?b}{}_2\text{u?c}{}_2\text{u)v}\text{(x, t) ? (0, 1) × (0, ∞)}$

, with homogeneous Dirichlet boundary conditions. From a global bifurcation view point, the dependency of steady-states on the parameters a_i, b_i, c_i and d_i (i = 1, 2) is investigated. In particular, bifurcation of coexist ence solutions amd their stabilities are our main interests.     

Coriolis intensity perturbations in the SO2 molecule: Experimental determination of the relative signs of (∂μ∂Qi)

The Coriolis interactions between ν₁ and ν₃, and between ν₂ and ν₃ in SO₂ have been analyzed to obtain the signs of the products $\text{ζ}{}_{3.1}{}^{\mathrm{c}}\text{(}\text{?μ}{}^{\mathrm{a}}\text{?Q}{}_3\text{)(}\text{?μ}{}^{\mathrm{b}}\text{?Q}{}_1\text{)}$ and $\text{ζ}{}_{3.2}{}^{\mathrm{c}}\text{(}\text{?μ}{}^{\mathrm{a}}\text{?Q}{}_3\text{)(}\text{?μ}{}^{\mathrm{b}}\text{?Q}{}_2\text{)}$. It has been found that both of the signs of these products are positive. Then, relative signs of ($\text{?μ}\text{?Q}{}_1$) have been determined using the calculated values of the Coriolis zeta constants for the present definition of the normal coordinates. The obtained sign combination of ($\text{?μ}\text{?Q}{}_{\mathrm{i}}$) is ±(+?+), which agrees with the one predicted by the molecular orbital calculations. Using the sign combination (+?+), the polar tensors of S and O atoms were also calculated.     

The spectrum and structure of the He2 molecule: Characterization of the triplet states associated with the UAO's 4pπ and 5pπ

The He₂ band systems $\text{4pπ i}{}^3\text{Π}{}_{\mathrm{g}}\text{→ 2s a}{}^3\text{Σ}{}_{\mathrm{u}}{}^{\mathrm{+}}$ and $\text{5pπ l}{}^3\text{Π}{}_{\mathrm{g}}\text{→ 2s a}{}^3\text{Σ}{}_{\mathrm{u}}{}^{\mathrm{+}}$ are described in detail, and the i and l states characterized. A number of significant perturbations in the i and l states are identified, and the possible perturber states discussed. The following molecular constants (cm^?1) are reported:

     

8.

Electron-hole interaction in the presence of excitons     

J.H. Collet  T. Amand 《Solid State Communications》1984,52(1):53-56

We calculate the effective electron-hole interaction V_re in the presence of an exciton gas, which reads in real space:

$\text{V}{}_{\mathrm{re}}\text{(r)=}\text{?e}{}^2\text{r}\text{{1+}\text{∑}\text{i=1}\text{4}\text{(?1)}{}^{\mathrm{i}}\text{C}{}_{\mathrm{i}}\text{exp}\text{(?Z}{}_{\mathrm{i}}\text{r}\text{a}\text{}}$

The parameters C_i and Z_i are given explicitly for GaAs. For this material, we show the binding energy of the exciton is weakly modified so long as $\text{8πR}{}_0\text{?}{}_{\mathrm{ex}}\text{a}{}_0{}^3\text{kT?1}$. (R₀, exciton Rydberg, a₀ exciyon radius, ?_ex exciton density, T temperature).     

9.

Kerr-effect and dielectric tensor elements of magnetite (Fe₃O₄) between 0.5 and 4.3 eV     

Xuxin Zhang  J. Schoenes  P. Wachter 《Solid State Communications》1981,39(1):189-192

The complex polar Kerr effect (rotation and ellipticity) of magnetite single crystals has been measured at room temperature between 0.5 and 4.3 eV. From the magneto-optical data and the optical constants, the off-diagonal elements (?_xy) of the dielectric tensor has been derived. Three well separated magneto-optical transitions have been indentified. At about 0.75 eV one strong magneto-optical structure with a diamagnetic line shape is assigned to a $\text{3d}{}^6\text{→3d}{}^5\text{(}{}^6\text{A}{}_{\mathrm{1g}}\text{) 4s}$ transition from Fe²⁺ in octahedral sites. Two other structures with paramagnetic line shapes near 1.85 and 2.90 eV are assigned to the orbital promotion processes $\text{3d}{}^6\text{(Fe}{}^{\mathrm{2+}}{}_{\mathrm{oct}}\text{)→3d}{}^5\text{(}{}^4\text{T}{}_{\mathrm{1g}}\text{) 4s}$ and $\text{3d}{}^5\text{(Fe}{}^{\mathrm{3+}}{}_{\mathrm{tet}}\text{)→3d}{}^4\text{(}{}^5\text{T}{}_2\text{) 4s}$, respectively, which take into account Fe 3d^n?1 final state effects.     

10.

Reflection of long waves by interfaces     

John Lekner 《Physica A》1982,112(3):544-556

We derive comparison identities for waves satisfying the equation d²Ψ/dz²+q²(z)Ψ=0. One of these identities is used to show that to second order in the product (wavenumber component normal to interface) × (interface thickness), the reflection amplitude is given by $\text{r=(1?2q}{}_1\text{q}{}_2\text{l}{}^2\text{)}\text{(q}{}_1\text{?q}{}_2\text{)}\text{(q}{}_1\text{+q}{}_2\text{)}$, where l is a legnth determined by the deviation of the interface profile from a step, and q₁, q₂ are the normal components of the wave numbers in media 1 and 2 on either side of the interface. For the continuous interfaces discussed, l is about two-fifths of the 10–90 interface thickness. The corresponding formula for the transmission amplitude is $\text{t=(1+}\text{1}\text{2}\text{(q}{}_1\text{?q}{}_2\text{)}{}^2\text{l}{}^2\text{)}\text{2q}{}_1\text{(q}{}_1\text{+q}{}_2\text{)}$.     

11.

Study of the ⁹¹Zr(d, ³He)⁹⁰Y reaction     

S. Cochavi  S. Gilad  M.A. Moinester  J. Alster  M. Buenerd  P. Martin 《Nuclear Physics A》1974,233(1):73-80

The ⁹¹Zr(d, ³He) reaction was studied at a deuteron energy of 28 MeV. Angular distributions were measured from 13° to 47°; l_p values were extracted for the prominent lines of ⁹⁰Y. The l_p values and transition strengths were determined by DWBA analysis. The angular distributions for the $\text{(π}\text{p}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}\text{)(ν}\text{d}{}_{\mathrm{<mtext>5</mtext><mtext>2</mtext>}}\text{)}$ doublet (g.s. and 0.20 MeV state) exhibit the characteristic l = 1 shape. States at 1.42, 1.57, 1.64 and 1.81 MeV were also populated strongly in the (d, ³He) reaction; the 1.42, 1.57 and 1.81 MeV levels contain l= 1 transition strength and are most likely members of the $\text{(π}\text{p}{}_{\mathrm{<mtext>3</mtext><mtext>2</mtext>}}{}^{\mathrm{?1}}\text{)(ν}\text{d}{}_{\mathrm{<mtext>5</mtext><mtext>2</mtext>}}\text{)}$ multiplet. The 2.03 MeV state has a characteristic l = 3 angular distribution and is suggested to be the only member of the $\text{(π}\text{f}{}_{\mathrm{<mtext>3</mtext><mtext>2</mtext>}}{}^{\mathrm{?1}}\text{)(ν}\text{d}{}_{\mathrm{<mtext>5</mtext><mtext>2</mtext>}}\text{)}$ sextet to be unambiguously observed in this study, most probably the 5^? or 4^? member. The members of the $\text{(π}\text{g}{}_{\mathrm{<mtext>5</mtext><mtext>2</mtext>}}\text{)(ν}\text{d}{}_{\mathrm{<mtext>9</mtext><mtext>2</mtext>}}\text{)}$ sextet were populated weakly (less than 100 μb/sr) in this reaction.     

12.

The 85Rb(p,d)84Rb reaction     

S. Shastry  R.A. Emigh  R.J. Peterson  R.E. Anderson 《Nuclear Physics A》1978,304(1):40-50

The spectrum seen in single neutron pickup leading to the doubly odd nucleus ⁸⁴Rb is remarkably clean, with only five levels populated by l = 4 and six by l = 1 transitions. A simple 2J+1 weighting for the l = 4 data, combined with previous information on ⁸⁴Rb, allowed the J^π = 2^?–7^? states of the ($\text{v}\text{g}{}_{\mathrm{<mtext>9</mtext><mtext>2</mtext>}}{}^{\mathrm{?3}}\text{? π}\text{f}{}_{\mathrm{<mtext>5</mtext><mtext>2</mtext>}}{}^{\mathrm{?3}}$) multiplet to be identified. These data are used to determine the two-hole $\text{π}\text{f}{}_{\mathrm{<mtext>5</mtext><mtext>2</mtext>}}{}^{\mathrm{?1}}\text{-v}\text{g}{}_{\mathrm{<mtext>9</mtext><mtext>2</mtext>}}{}^{\mathrm{?}}$ interaction matrix elements.     

13.

The A-dependence of J/ψ-particle inclusive distributions     

Yu.M. Antipov  V.A. Bessubov  N.P. Budanov  Yu.P. Gorin  S.P. Denisov  S.V. Klimenko  A.A. Lebedev  Yu.V. Mikhailov  A.I. Petrukhin  S.A. Polovnikov  V.N. Roinishvili  D.A. Stoyanova  F.A. Yotch 《Physics letters. [Part B]》1978,76(2):235-236

The differential cross sections $\text{d}\text{σ}\text{d}\text{x}$ and $\text{d}\text{σ}\text{d}\text{p}{}_{\mathrm{t}}{}^2$ of inclusive J/ψ production by 43 GeV/c π^? off Be, Cu and W nuclei have been measured. Fitting $\text{d}\text{σ}\text{d}\text{p}{}_{\mathrm{t}}{}^2\text{～ A}{}^{\mathrm{\alpha }}\text{(p}{}_{\mathrm{t}}{}^2\text{)}$ we observed the increase of α with p_t².     

14.

Polariton modes at the interface between two conducting or dielectric media     

P. Halevi 《Surface science》1978,76(1):64-90

A review of polariton modes at interfaces composed of two semiinfinite, homogeneous, and isotropic media is given. Both media are characterized by frequency-dependent dielectric functions ?_i(ω), i = 1, 2, and may become “interface-wave-active” in different frequency regions. The conditions for the existance of propagation windows are analyzed and applied to two particular cases: an interface composed of (a) two dielectrics with dielectric functions $\text{?}{}_{\mathrm{i}}\text{= ?}{}_{\mathrm{?\infty i}}\text{(}\text{ω}{}^2\text{ω}{}_{\mathrm{<mtext>Li</mtext>}}{}^2\text{ω}{}^2\text{ω}{}_{\mathrm{<mtext>T</mtext><mtext>i</mtext>}}{}^2$, where ?_t8i are the dielectric constants for very large frequencies and ωTi and ωLi are the transverse and longitudinal phonon frequencies; (b) two conductors with dielectric functions $\text{?}{}_{\mathrm{i}}\text{= ?}{}_{\mathrm{\infty i}}\text{(}\text{1 ?ω}{}_{\mathrm{i}}{}^2\text{ω}{}^2\text{)}$, where ω_iare the plasma frequencies. In the first case there exist two propagation windows in the infrared region, while in the second case there is one propagation window in the ultraviolet, visible, or infrared region. The dispersion relations of the modes and their decay distances into the two media are presented, and various damping effects are discussed. The review is concluded with theoretical results on the optical excitation and detection (ATR) of the interface modes.     

15.

The giant Gamow-Teller resonance states     

Toshio Suzuki 《Nuclear Physics A》1982,379(1):110-124

The mean energy of the giant Gamow-Teller resonance state (GTS) is studied, which is defined by the non-energy-weighted and the linearly energy-weighted sum of the strengths for Σ^A_i = 1^τi?σⁱ? Using Bohr and Mottelson's hamiltonian with the ξl· σ force, the difference between the mean energies of GTS and the isobaric analog state (IAS) is expressed as$\text{E}{}_{\mathrm{GTS}}\text{?E}{}_{\mathrm{IAS}}\text{,≈ 2〈π¦Σ}{}^{\mathrm{A}}{}_{\mathrm{i}}\text{=1ξ}{}_{\mathrm{i}}\text{l}{}_{\mathrm{i}}\text{· σ}{}_{\mathrm{i}}\text{¦π〉/ (3T}{}_0\text{-4(k}{}_{\mathrm{\tau }}\text{?k}{}_{\mathrm{\sigma \tau }}\text{) T}{}_0$. The observed energy systematics is well explained by k_τ?k_{στ≈ 4/A MeV}. The relationship between the mean energies and the excitation energies of the collective states in the random phase approximation for charge-exchange excitations is discussed in a simple model. From the excitation energy systematics of GTS, the values of k_στ and the Migdal parameter g′ are estimated to be about $\text{k}{}_{\mathrm{\sigma \tau }}\text{=}\text{(16–24)}\text{A}\text{MeV and}\text{g′ = 0.49–0.72}$, respectively.     

16.

Contributions of operators of twist two and higher in large n moments of structure functions     

Moshe Moshe 《Physics letters. [Part B]》1981,98(4):297-300

Though high twist terms are becoming important as x→1, or equivalently, in large n moments, their detection in this regime in deep inelastic lepton scattering needs special caution. The high order terms in the twist two component are strongly dependent on n; one finds that at $\text{Q}{}^2\text{?Q}{}^2{}_7\text{?Λ}{}^2\text{a}{}_{\mathrm{k}}\text{exp}\text{[α}{}_{\mathrm{k}}\text{(}\text{log}\text{n)}{}^{\mathrm{<mtext>2?1</mtext><mtext>k</mtext>}}\text{(}\text{1+b}{}_{\mathrm{k}}\text{log}\text{n}\text{)]}$ the perturbative expansion is invalid whereas higher twist terms are important at $\text{Q}{}^2\text{?Q}{}_1{}^2\text{= Λ}{}^2\text{nC}$. Since $\text{Q}{}_7{}^2$ grows very fast with n the necessary requirement for any deep inelastic phenomenological analysis, namely $\text{Q}{}_1{}^2\text{?Q}{}_7{}^2$, cannot hold for too large moments. The scheme dependence of a_k, α_k and b_k is also discussed.     

17.

Particle-hole multiplets in ⁴⁰Ca observed in the ⁴¹Ca(τ, α) reaction     

D. Cline  M.J.A. De Voigt  P.B. Vold  Ole Hansen  O. Nathan  D. Sinclair 《Nuclear Physics A》1974,233(1):91-104

Energy levels in ⁴⁰Ca up to 10.2 MeV have been studied in the neutron pickup reaction ⁴¹Ca(τ, α)⁴⁰Ca with 20 MeV bombarding energy. Thirty excited states have been identified and angular distributions have been measured in the interval from 5° to 40° by means of a split-pole magnetic spectrometer. The angular distributions together with DW calculations have been used to extract l_n values and spectroscopic factors. The l_n = 2 strength distribution for the $\text{f}{}_{\mathrm{<mtext>7</mtext><mtext>2</mtext>}}\text{d}{}_{\mathrm{<mtext>3</mtext><mtext>2</mtext>}}{}^{\mathrm{?1}}$ particle-hole levels is compared to the l_p = 3 strength distribution from pr stripping data.     

18.

Low-lying levels of ¹⁴⁰Pr     

S.G. Hussein  N.E. Sanderson  R.G. Summers-Gill 《Nuclear Physics A》1974,219(2):407-421

The doubly odd nucleus ¹⁴⁰Pr has been investigated by means of the ¹⁴¹Pr(d, t)¹⁴⁰Pr and ¹⁴⁰Ce(p, nγ)¹⁴⁰Pr reactions. Twenty-eight levels, up to 1300 keV excitation, were observed in the pickup study. DWBA analysis was used to determine l-values and spectroscopic factors for all but a few which are very weakly populated. Gamma-ray angular distributions, measured at E_p = 4.78 MeV for the five strongest γ-rays, show appreciable nuclear alignment and demonstrate the feasibility of such experiments in this mass region. Taken together, the two studies have permitted the identification of the 12 levels expected from the low-lying ($\text{π2}\text{d}{}_{\mathrm{<mtext>5</mtext><mtext>2</mtext>}}\text{ν2}\text{d}{}_{\mathrm{<mtext>3</mtext><mtext>2</mtext>}}{}^{\mathrm{?1}}$), ($\text{π2}\text{d}{}_{\mathrm{<mtext>5</mtext><mtext>2</mtext>}}\text{ν3}\text{s}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}{}^{\mathrm{?1}}$), ($\text{π1}\text{g}{}_{\mathrm{<mtext>7</mtext><mtext>2</mtext>}}\text{ν2}\text{d}{}_{\mathrm{<mtext>3</mtext><mtext>2</mtext>}}{}^{\mathrm{?1}}$) and (π1g_{$\text{7}\text{2}$}ν3s_{$\text{1}\text{2}$}^?1) configurations. Tenta assignments for the strong odd-parity states are suggested on the basis of their spectroscopic factors.     

19.

QED distributions for hard photon emission in e⁺e⁻ → μ⁺μ⁻γ     

E.A. Kuraev  G.V. Meledin 《Nuclear Physics B》1977,122(3):485-492

The hard photon emission in e⁺e^? → μ⁺μ^?γ is investigated to order α³. Formulas for a number of distributions are obtained, when neglecting terms of order (m_e/?)² and (m_μ/?)². Both charge-even and charge-odd contributions are calculated. The total contribution to the charge asymmetry parameter

$\text{? =}\text{[}\text{d}\text{σ(θ)}\text{d}\text{O}{}_{\mathrm{\mu }}{}^{\mathrm{+}}\text{?}\text{d}\text{Oσ(π?θ)}\text{d}\text{O}{}_{\mathrm{\mu }}{}^{\mathrm{+}}\text{]}\text{[}\text{d}\text{σ(θ)}\text{d}\text{O}{}_{\mathrm{\mu }}{}^{\mathrm{+}}\text{+}\text{d}\text{σ(π ? σ)}\text{d}\text{O}{}_{\mathrm{\mu }}{}^{\mathrm{+}}\text{]}$

does not exceed 5% for the c.m.s. energy 2? = 3 GeV.     

20.

Perturbations in the vibration-rotation-torsion energy levels of an ethane molecule exhibiting internal rotation splittings     

Jon T Hougen 《Journal of Molecular Spectroscopy》1980,82(1):92-116

Various examples of perturbations in the vibration-rotation-torsion energy levels of an ethane molecule exhibiting internal rotation splittings are discussed, both from the point of view of the point group D_3d, appropriate when internal rotation tunneling effects cannot be observed, and from the point of view of the group $\text{G}{}_{36}{}^2$, appropriate when internal rotation tunneling in ethane leads to observable splittings in the spectrum. It is found, for perturbations allowed in both D_3d and $\text{G}{}_{36}{}^2$, that each of the two torsional components of the perturbed D_3d vibration-rotation level can in principle interact with a “corresponding” torsional component in the perturbing vibration-rotation level. It is found for perturbations forbidden in D_3d but allowed in $\text{G}{}_{36}{}^2$, which all occur between D_3d vibrational levels of different g, u parity, that only one of the two torsional components of the perturbed D_3d vibration-rotation level can interact with a corresponding torsional component in the perturbing vibration-rotation level. Some of the perturbations examined give intensity to otherwise forbidden transitions in such a way that perturbation-induced transitions can be used in conjunction with normally allowed transitions to determine the sum of the internal rotation splittings for two rotational levels differing in K by three units.     

State	$\text{ω}{}_{\mathrm{e}}$	$\text{xω}{}_{\mathrm{e}}$	$\text{B}{}_{\mathrm{e}}$	$\text{α}{}_{\mathrm{e}}$	$\text{r}{}_{\mathrm{e}}\text{(}\text{A}\text{?}\text{)}$
$\text{i}{}^3\text{Π}{}_{\mathrm{g}}$	1707.95	35.00	7.242g	0.222	1.0782
$\text{l}{}^2\text{Π}{}_{\mathrm{g}}$	1703.86	34.97	7.2264	0.2188	1.0794

Electron-hole interaction in the presence of excitons

We calculate the effective electron-hole interaction V_re in the presence of an exciton gas, which reads in real space:

$\text{V}{}_{\mathrm{re}}\text{(r)=}\text{?e}{}^2\text{r}\text{{1+}\text{∑}\text{i=1}\text{4}\text{(?1)}{}^{\mathrm{i}}\text{C}{}_{\mathrm{i}}\text{exp}\text{(?Z}{}_{\mathrm{i}}\text{r}\text{a}\text{}}$

The parameters C_i and Z_i are given explicitly for GaAs. For this material, we show the binding energy of the exciton is weakly modified so long as $\text{8πR}{}_0\text{?}{}_{\mathrm{ex}}\text{a}{}_0{}^3\text{kT?1}$. (R₀, exciton Rydberg, a₀ exciyon radius, ?_ex exciton density, T temperature).     

Kerr-effect and dielectric tensor elements of magnetite (Fe3O4) between 0.5 and 4.3 eV

The complex polar Kerr effect (rotation and ellipticity) of magnetite single crystals has been measured at room temperature between 0.5 and 4.3 eV. From the magneto-optical data and the optical constants, the off-diagonal elements (?_xy) of the dielectric tensor has been derived. Three well separated magneto-optical transitions have been indentified. At about 0.75 eV one strong magneto-optical structure with a diamagnetic line shape is assigned to a $\text{3d}{}^6\text{→3d}{}^5\text{(}{}^6\text{A}{}_{\mathrm{1g}}\text{) 4s}$ transition from Fe²⁺ in octahedral sites. Two other structures with paramagnetic line shapes near 1.85 and 2.90 eV are assigned to the orbital promotion processes $\text{3d}{}^6\text{(Fe}{}^{\mathrm{2+}}{}_{\mathrm{oct}}\text{)→3d}{}^5\text{(}{}^4\text{T}{}_{\mathrm{1g}}\text{) 4s}$ and $\text{3d}{}^5\text{(Fe}{}^{\mathrm{3+}}{}_{\mathrm{tet}}\text{)→3d}{}^4\text{(}{}^5\text{T}{}_2\text{) 4s}$, respectively, which take into account Fe 3d^n?1 final state effects.     

Reflection of long waves by interfaces

We derive comparison identities for waves satisfying the equation d²Ψ/dz²+q²(z)Ψ=0. One of these identities is used to show that to second order in the product (wavenumber component normal to interface) × (interface thickness), the reflection amplitude is given by $\text{r=(1?2q}{}_1\text{q}{}_2\text{l}{}^2\text{)}\text{(q}{}_1\text{?q}{}_2\text{)}\text{(q}{}_1\text{+q}{}_2\text{)}$, where l is a legnth determined by the deviation of the interface profile from a step, and q₁, q₂ are the normal components of the wave numbers in media 1 and 2 on either side of the interface. For the continuous interfaces discussed, l is about two-fifths of the 10–90 interface thickness. The corresponding formula for the transmission amplitude is $\text{t=(1+}\text{1}\text{2}\text{(q}{}_1\text{?q}{}_2\text{)}{}^2\text{l}{}^2\text{)}\text{2q}{}_1\text{(q}{}_1\text{+q}{}_2\text{)}$.     

Study of the 91Zr(d, 3He)90Y reaction

The ⁹¹Zr(d, ³He) reaction was studied at a deuteron energy of 28 MeV. Angular distributions were measured from 13° to 47°; l_p values were extracted for the prominent lines of ⁹⁰Y. The l_p values and transition strengths were determined by DWBA analysis. The angular distributions for the $\text{(π}\text{p}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}\text{)(ν}\text{d}{}_{\mathrm{<mtext>5</mtext><mtext>2</mtext>}}\text{)}$ doublet (g.s. and 0.20 MeV state) exhibit the characteristic l = 1 shape. States at 1.42, 1.57, 1.64 and 1.81 MeV were also populated strongly in the (d, ³He) reaction; the 1.42, 1.57 and 1.81 MeV levels contain l= 1 transition strength and are most likely members of the $\text{(π}\text{p}{}_{\mathrm{<mtext>3</mtext><mtext>2</mtext>}}{}^{\mathrm{?1}}\text{)(ν}\text{d}{}_{\mathrm{<mtext>5</mtext><mtext>2</mtext>}}\text{)}$ multiplet. The 2.03 MeV state has a characteristic l = 3 angular distribution and is suggested to be the only member of the $\text{(π}\text{f}{}_{\mathrm{<mtext>3</mtext><mtext>2</mtext>}}{}^{\mathrm{?1}}\text{)(ν}\text{d}{}_{\mathrm{<mtext>5</mtext><mtext>2</mtext>}}\text{)}$ sextet to be unambiguously observed in this study, most probably the 5^? or 4^? member. The members of the $\text{(π}\text{g}{}_{\mathrm{<mtext>5</mtext><mtext>2</mtext>}}\text{)(ν}\text{d}{}_{\mathrm{<mtext>9</mtext><mtext>2</mtext>}}\text{)}$ sextet were populated weakly (less than 100 μb/sr) in this reaction.     

The 85Rb(p,d)84Rb reaction

The spectrum seen in single neutron pickup leading to the doubly odd nucleus ⁸⁴Rb is remarkably clean, with only five levels populated by l = 4 and six by l = 1 transitions. A simple 2J+1 weighting for the l = 4 data, combined with previous information on ⁸⁴Rb, allowed the J^π = 2^?–7^? states of the ($\text{v}\text{g}{}_{\mathrm{<mtext>9</mtext><mtext>2</mtext>}}{}^{\mathrm{?3}}\text{? π}\text{f}{}_{\mathrm{<mtext>5</mtext><mtext>2</mtext>}}{}^{\mathrm{?3}}$) multiplet to be identified. These data are used to determine the two-hole $\text{π}\text{f}{}_{\mathrm{<mtext>5</mtext><mtext>2</mtext>}}{}^{\mathrm{?1}}\text{-v}\text{g}{}_{\mathrm{<mtext>9</mtext><mtext>2</mtext>}}{}^{\mathrm{?}}$ interaction matrix elements.     

The A-dependence of J/ψ-particle inclusive distributions

The differential cross sections $\text{d}\text{σ}\text{d}\text{x}$ and $\text{d}\text{σ}\text{d}\text{p}{}_{\mathrm{t}}{}^2$ of inclusive J/ψ production by 43 GeV/c π^? off Be, Cu and W nuclei have been measured. Fitting $\text{d}\text{σ}\text{d}\text{p}{}_{\mathrm{t}}{}^2\text{～ A}{}^{\mathrm{\alpha }}\text{(p}{}_{\mathrm{t}}{}^2\text{)}$ we observed the increase of α with p_t².     

Polariton modes at the interface between two conducting or dielectric media

A review of polariton modes at interfaces composed of two semiinfinite, homogeneous, and isotropic media is given. Both media are characterized by frequency-dependent dielectric functions ?_i(ω), i = 1, 2, and may become “interface-wave-active” in different frequency regions. The conditions for the existance of propagation windows are analyzed and applied to two particular cases: an interface composed of (a) two dielectrics with dielectric functions $\text{?}{}_{\mathrm{i}}\text{= ?}{}_{\mathrm{?\infty i}}\text{(}\text{ω}{}^2\text{ω}{}_{\mathrm{<mtext>Li</mtext>}}{}^2\text{ω}{}^2\text{ω}{}_{\mathrm{<mtext>T</mtext><mtext>i</mtext>}}{}^2$, where ?_t8i are the dielectric constants for very large frequencies and ωTi and ωLi are the transverse and longitudinal phonon frequencies; (b) two conductors with dielectric functions $\text{?}{}_{\mathrm{i}}\text{= ?}{}_{\mathrm{\infty i}}\text{(}\text{1 ?ω}{}_{\mathrm{i}}{}^2\text{ω}{}^2\text{)}$, where ω_iare the plasma frequencies. In the first case there exist two propagation windows in the infrared region, while in the second case there is one propagation window in the ultraviolet, visible, or infrared region. The dispersion relations of the modes and their decay distances into the two media are presented, and various damping effects are discussed. The review is concluded with theoretical results on the optical excitation and detection (ATR) of the interface modes.     

The giant Gamow-Teller resonance states

The mean energy of the giant Gamow-Teller resonance state (GTS) is studied, which is defined by the non-energy-weighted and the linearly energy-weighted sum of the strengths for Σ^A_i = 1^τi?σⁱ? Using Bohr and Mottelson's hamiltonian with the ξl· σ force, the difference between the mean energies of GTS and the isobaric analog state (IAS) is expressed as$\text{E}{}_{\mathrm{GTS}}\text{?E}{}_{\mathrm{IAS}}\text{,≈ 2〈π¦Σ}{}^{\mathrm{A}}{}_{\mathrm{i}}\text{=1ξ}{}_{\mathrm{i}}\text{l}{}_{\mathrm{i}}\text{· σ}{}_{\mathrm{i}}\text{¦π〉/ (3T}{}_0\text{-4(k}{}_{\mathrm{\tau }}\text{?k}{}_{\mathrm{\sigma \tau }}\text{) T}{}_0$. The observed energy systematics is well explained by k_τ?k_{στ≈ 4/A MeV}. The relationship between the mean energies and the excitation energies of the collective states in the random phase approximation for charge-exchange excitations is discussed in a simple model. From the excitation energy systematics of GTS, the values of k_στ and the Migdal parameter g′ are estimated to be about $\text{k}{}_{\mathrm{\sigma \tau }}\text{=}\text{(16–24)}\text{A}\text{MeV and}\text{g′ = 0.49–0.72}$, respectively.     

Contributions of operators of twist two and higher in large n moments of structure functions

Though high twist terms are becoming important as x→1, or equivalently, in large n moments, their detection in this regime in deep inelastic lepton scattering needs special caution. The high order terms in the twist two component are strongly dependent on n; one finds that at $\text{Q}{}^2\text{?Q}{}^2{}_7\text{?Λ}{}^2\text{a}{}_{\mathrm{k}}\text{exp}\text{[α}{}_{\mathrm{k}}\text{(}\text{log}\text{n)}{}^{\mathrm{<mtext>2?1</mtext><mtext>k</mtext>}}\text{(}\text{1+b}{}_{\mathrm{k}}\text{log}\text{n}\text{)]}$ the perturbative expansion is invalid whereas higher twist terms are important at $\text{Q}{}^2\text{?Q}{}_1{}^2\text{= Λ}{}^2\text{nC}$. Since $\text{Q}{}_7{}^2$ grows very fast with n the necessary requirement for any deep inelastic phenomenological analysis, namely $\text{Q}{}_1{}^2\text{?Q}{}_7{}^2$, cannot hold for too large moments. The scheme dependence of a_k, α_k and b_k is also discussed.     

Particle-hole multiplets in 40Ca observed in the 41Ca(τ, α) reaction

Energy levels in ⁴⁰Ca up to 10.2 MeV have been studied in the neutron pickup reaction ⁴¹Ca(τ, α)⁴⁰Ca with 20 MeV bombarding energy. Thirty excited states have been identified and angular distributions have been measured in the interval from 5° to 40° by means of a split-pole magnetic spectrometer. The angular distributions together with DW calculations have been used to extract l_n values and spectroscopic factors. The l_n = 2 strength distribution for the $\text{f}{}_{\mathrm{<mtext>7</mtext><mtext>2</mtext>}}\text{d}{}_{\mathrm{<mtext>3</mtext><mtext>2</mtext>}}{}^{\mathrm{?1}}$ particle-hole levels is compared to the l_p = 3 strength distribution from pr stripping data.     

Low-lying levels of 140Pr

The doubly odd nucleus ¹⁴⁰Pr has been investigated by means of the ¹⁴¹Pr(d, t)¹⁴⁰Pr and ¹⁴⁰Ce(p, nγ)¹⁴⁰Pr reactions. Twenty-eight levels, up to 1300 keV excitation, were observed in the pickup study. DWBA analysis was used to determine l-values and spectroscopic factors for all but a few which are very weakly populated. Gamma-ray angular distributions, measured at E_p = 4.78 MeV for the five strongest γ-rays, show appreciable nuclear alignment and demonstrate the feasibility of such experiments in this mass region. Taken together, the two studies have permitted the identification of the 12 levels expected from the low-lying ($\text{π2}\text{d}{}_{\mathrm{<mtext>5</mtext><mtext>2</mtext>}}\text{ν2}\text{d}{}_{\mathrm{<mtext>3</mtext><mtext>2</mtext>}}{}^{\mathrm{?1}}$), ($\text{π2}\text{d}{}_{\mathrm{<mtext>5</mtext><mtext>2</mtext>}}\text{ν3}\text{s}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}{}^{\mathrm{?1}}$), ($\text{π1}\text{g}{}_{\mathrm{<mtext>7</mtext><mtext>2</mtext>}}\text{ν2}\text{d}{}_{\mathrm{<mtext>3</mtext><mtext>2</mtext>}}{}^{\mathrm{?1}}$) and (π1g_{$\text{7}\text{2}$}ν3s_{$\text{1}\text{2}$}^?1) configurations. Tenta assignments for the strong odd-parity states are suggested on the basis of their spectroscopic factors.     

QED distributions for hard photon emission in e+e− → μ+μ−γ

The hard photon emission in e⁺e^? → μ⁺μ^?γ is investigated to order α³. Formulas for a number of distributions are obtained, when neglecting terms of order (m_e/?)² and (m_μ/?)². Both charge-even and charge-odd contributions are calculated. The total contribution to the charge asymmetry parameter

$\text{? =}\text{[}\text{d}\text{σ(θ)}\text{d}\text{O}{}_{\mathrm{\mu }}{}^{\mathrm{+}}\text{?}\text{d}\text{Oσ(π?θ)}\text{d}\text{O}{}_{\mathrm{\mu }}{}^{\mathrm{+}}\text{]}\text{[}\text{d}\text{σ(θ)}\text{d}\text{O}{}_{\mathrm{\mu }}{}^{\mathrm{+}}\text{+}\text{d}\text{σ(π ? σ)}\text{d}\text{O}{}_{\mathrm{\mu }}{}^{\mathrm{+}}\text{]}$

does not exceed 5% for the c.m.s. energy 2? = 3 GeV.     

Perturbations in the vibration-rotation-torsion energy levels of an ethane molecule exhibiting internal rotation splittings

Various examples of perturbations in the vibration-rotation-torsion energy levels of an ethane molecule exhibiting internal rotation splittings are discussed, both from the point of view of the point group D_3d, appropriate when internal rotation tunneling effects cannot be observed, and from the point of view of the group $\text{G}{}_{36}{}^2$, appropriate when internal rotation tunneling in ethane leads to observable splittings in the spectrum. It is found, for perturbations allowed in both D_3d and $\text{G}{}_{36}{}^2$, that each of the two torsional components of the perturbed D_3d vibration-rotation level can in principle interact with a “corresponding” torsional component in the perturbing vibration-rotation level. It is found for perturbations forbidden in D_3d but allowed in $\text{G}{}_{36}{}^2$, which all occur between D_3d vibrational levels of different g, u parity, that only one of the two torsional components of the perturbed D_3d vibration-rotation level can interact with a corresponding torsional component in the perturbing vibration-rotation level. Some of the perturbations examined give intensity to otherwise forbidden transitions in such a way that perturbation-induced transitions can be used in conjunction with normally allowed transitions to determine the sum of the internal rotation splittings for two rotational levels differing in K by three units.