Analysis of the 2770-Å emission system in I2

A weak emission spectrum of I₂ near 2770 Å is reanalyzed and found to to minate on the A(1u³Π) state. The assigned bands span v″ levels 5–19 and v′ levels 0–8. The new assignment is corroborated by isotope shifts, band profile simulations, and Franck-Condon calculations. The excited state is an ion-pair state, probably the 1g state which tends toward $\text{I}{}^{\mathrm{?}}\text{(}{}^1\text{S) +}\text{I}{}^{\mathrm{+}}\text{(}{}^3\text{P}{}_1\text{)}$. In combination with other results for the A state, the analysis yields the following spectroscopic constants: T″_e = 10 907 cm^?1, $\text{D}$″_e = 1640 cm^?1, ω″_e = 95 cm^?1, $\text{R″}{}_{\mathrm{e}}\text{= 3.06}\text{A}\text{?}$; T′_e = 47 559.1 cm^?1, ω′_e = 106.60 cm^?1, $\text{R′}{}_{\mathrm{e}}\text{= 3.53}\text{A}\text{?}$.     

Defect dominated conductivity in Zn3P2

The electrical resistivity and Hall coefficient of Zn₃P₂ have been measured for single crystal and thin polycrystalline film samples which were annealed over a range of equilibrium vapor compositions and temperatures. The room temperature electrical resistivity of single crystal samples annealed at 573 K varied from approximately 10⁵Ω-cm for single crystals heated in equilibrium with zinc to 10 Ω-cm for those annealed in a phosphorus rich ambient. Hall measurements indicate that a variation in carrier concentration is responsible for these changes. The experimentally observed dependence of carrier concentration [h° ], (cm^?3) on phosphorus pressure is given by [h°] = 1.32 · 10¹⁶ [p(P₄)]^0.13 for samples annealed at 573 K. The experimentally determined pressure dependence is in good agreement with a model based on phosphorus interstitials acting as acceptors. The pressure and temperature dependence of the carrier concentration yield the equilibrium constant K_I for the formation of interstitial phosphorus defects according to the reaction

$\text{1}\text{4}\text{P}{}_4\text{→ P′}{}_{\mathrm{i}}\text{+ h°}$

where

$\text{K}{}_{\mathrm{I}}\text{= 10}{}^{\mathrm{42.4\; \pm \; 2}}\text{cm}{}^{\mathrm{?6}}\text{torr}{}^{0.25}\text{[p(P}{}_4\text{)]}{}^{\mathrm{?0.25}}\text{exp(?1.18}\text{ev}\text{kT}\text{)}$

. The accommodation of phosphorus interstitials is discussed in light of the crystal structure of Zn₃P₂.     

Evidence for a narrow peak in Ksoπ±π+π- at 2.6 gev in 12 gev/cpp interactions

We report the evidence for a narrow charged peak (5.5 s.d.), which we suggest calling the I, in the 6-prong-V⁰ topology of $\text{p}$p interactions at 12 GeV/c. The mass, widht and the product of cross section σ_I times the branching ratio BR into the final state (K_s^oτ±τ⁺τ^? are found to be: $\text{M}{}_{\mathrm{I}}\text{=2.60 ±}\text{0.01}\text{GeV}\text{/}\text{c}{}^2$, $\text{Γ}{}_{\mathrm{I}}\text{?}\text{0.018}\text{GeV}\text{/}\text{c}{}^2$, σ_I·BR≈20 μbarn     

Temperature dependence of ferromagnetic anisotropy energy in cubic crystals

The magnetic anisotropy constant K₁ for cubic ferromagnetic crystals has been discussed based on the general expressions derived by Yang for hexagon crystals. By matching the experimental data, we obtained

$\text{K}{}_1\text{(T,H)}\text{K}{}_1\text{(0,0)}\text{=?6.14}\text{I}\text{?}{}_{\mathrm{<mtext>5</mtext><mtext>2</mtext>}}\text{(T,H) + 3.36}\text{I}\text{?}\text{9}\text{2}\text{(T,H) + 4.88m}{}^2\text{(T,H) ?1.10[}\text{I}\text{?}\text{5}\text{2}\text{(T,H)]}{}^2$

for nickel, and $\text{K}{}_1\text{(T,H)/K}{}_1\text{(0,0)=I}{}_{\mathrm{<mtext>9</mtext><mtext>2</mtext>}}$ for iron, where Î_{$\text{5}\text{2}$} and Î_{$\text{9}\text{2}$} are the hyperbolic bessel functions of order 2 and 4 respectively and m is the reduced magnetization. Both expressions have a theoretical basis.     

The nuclear quadrupole interaction in Pr3+:LaF3 — An optical-RF double resonance measurement of the ground electronic state

The nuclear quadrupole hyperfine splittings of Pr³⁺ in LaF₃ have been measured for the ground electronic state using a RF optical resonance technique. A hamiltonian $\text{H}\text{= P[(I}{}^2{}_{\mathrm{z}}\text{?}\text{1}\text{3}\text{I(I+1) + (η/6)(I}{}^2{}_{\mathrm{+}}\text{?I}$²_-)] was fitted to the data with zP=4.185 ± 0.003 MHzandη = 0.105 ± 0.010. Linewidths of 180 kHz were observed.     

A study of the excited electronic states of 9-fluorenone

Some spectroscopic properties of the low-energy electronic states of 9-fluorenone have been examined. The spectra in paraffin matrices at 4.2°K show detailed vibrational spectra. Two fluorescence spectra are observed; a diffuse emission arises from 9-fluorenone crystals in the paraffin matrix, and a sharp emission is characteristic of the molecule. The sharp fluorescence is analyzed in terms of known a₁ vibrational fundamentals. The sharp absorption is a near mirror-image to the fluorescence, so Herzberg-Teller vibrations are not prominent. The polarization in the crystal spectrum allows this low-energy transition near 23 000 cm^?1 to be assigned ${}^1\text{B}{}_2\text{←}{}^1\text{A}{}_1$. Because there is no vibronic perturbation in fluorescence, and certainly no out-of-plane modes, a $\text{π}{}^1\text{← n}$ transition seen at about 26 000 cm^?1 is tentatively assigned ${}^1\text{B}{}_1\text{←}{}^1\text{A}{}_1$. Another sharp absorption system is seen at 31 000 cm^?1 in the paraffin matrices at 4.2°K (linewidth 6 cm^?1) but no fluorescence was detected. The polarized crystal spectrum indicated the assignment of this system and another very strong system at 40 000 cm^?1 to be ${}^1\text{B}{}_2\text{←}{}^1\text{A}{}_1$, while other systems at about 34 000 cm^?1 and 44 000 cm^?1 are ${}^1\text{A}{}_1\text{←}{}^1\text{A}{}_1$.The phosphorescence spectrum of pyrene-d₁₀ held in a single crystal of 9-fluorenone at 4.2°K has been recorded. No delayed fluorescence from the host crystal is observed at 4.2°K but is intense at 77°K. The energy difference between host and guest triplet levels is estimated to be about 900 cm^?1 allowing the lowest triplet state of 9-fluorenone to be placed at 17 800 cm^?1.     

Analysis of the B′3Σu− → B3Πg (0,0) emission band of molecular nitrogen

The (0,0) band of the $\text{B′}\text{Σ}{}_{\mathrm{u}}{}^{\mathrm{?}}\text{→ B}{}^3\text{Π}{}_{\mathrm{g}}$ emission (Infrared Afterglow) system of molecular nitrogen has been recorded with a resolution of 0.046 cm^?1 and a line position accuracy of 0.007 cm^?1. Six hundred and seventy-two lines are tabulated into a line list for the 1.53 μm (low-resolution) emission feature. Of these, 482 are assigned as members of the 27 branches of the B′ → B transition, while 150 are identified with the 1PG (3,6) band. Molecular constants for the v = 0 levels of the $\text{B′}{}^3\text{Σ}{}_{\mathrm{u}}{}^{\mathrm{?}}$ and B³Π_g states have been computed and tabulated.     

Landau-Placzek ratio of KBr single crystals—I

The Mandel'shtam-Brillouin and Gross scattering was measured for a series of purified KBr crystals. The ratio $\text{I}{}_{\mathrm{G}}\text{2I}{}_{\mathrm{MB}}$, which for a pure, perfect crystal would be the Landau-Placzek ratio, was found to vary with the type of reactive gas treatment used in the final purification. With these crystals both the longitudinal and mixed mode bands were observed with θ and φ equal to 90°. The ratio $\text{I}{}_{\mathrm{L}}\text{I}{}_{\mathrm{M}}$ was in agreement with calculated intensity ratios and the Δμ for these bands gave C₁₁ + C₁₂ = 41.6 GPa and C₄₄ = 5.18 GPa.     

Analysis of the Raman spectrum of SF6

The Raman active fundamentals ν₁(A1g), ν₂(Eg), ν₅(F2g), and the overtone 2ν₆ of SF₆ have been investigated with a higher resolution and the band origins were estimated to be: ν₁ = 774.53 cm^?1, ν₂ = 643.35 cm^?1, ν₅ = 523.5 cm^?1, and 2ν₆ = 693.8 cm^?1. Raman and infrared data have been combined for estimation of several anharmonicity constants. The ν₆ fundamental frequency is calculated as 347.0 cm^?1. From the analysis of the ν₂ Raman band, the following rotational constants of both the ground and upper states have been calculated:

$\text{B}{}_0\text{= 0.09111 ± 0.00005}\text{cm}{}^{\mathrm{?1}}\text{; D}{}_0\text{= (0.16±0.08)10}{}^{\mathrm{?7}}\text{cm}{}^{\mathrm{?1}}$

;

$\text{B}{}_2\text{= 0.09116 ± 0.00005}\text{cm}{}^{\mathrm{?1}}\text{; D}{}_2\text{= (0.18±0.04)10}{}^{\mathrm{?7}}\text{cm}{}^{\mathrm{?1}}$

.     

S1-S0 fluorescence after narrow band excitation of glyoxal: Single rotational level fluorescence and a technique for deconvolution of Doppler congested absorptions

Individual rovibronic transitions are isolated at high resolution from a crowded absorption feature with a fluorescence excitation technique which is based on detection of fluorescence from one and only one rovibronic level. The method is illustrated by resolving four rovibronic transitions from the single rotational line-like feature in the 0, 0 band of the ${}^1\text{A}{}_{\mathrm{u}}\text{←}{}^1\text{A}{}_{\mathrm{g}}$ (S₁ ← S₀) absorption of glyoxal vapor. The rotational structure of the 5₁⁰ fluorescence band is studied as a function of tuning a narrow-band laser line (linewidth < 10^?4 cm^?1) to various positions in and near this absorption feature. The fluorescence structure proves an extremely sensitive tool for detecting small absorptions, with emission from 12 rovibronic levels being identified. One of the spectra so obtained is a close approximation of true single rotational level fluorescence.     

Rotation-vibration analysis of the Coriolis-coupled ν5g, ν6g, ν8g and ν9 bands of H2CCO

Medium resolution infrared grating spectra of gaseous ketene, H₂CCO were recorded between 1000 and 400 cm^?1, both at instrument temperature (40°C) and with cooling (?40°C). Interferometric Fourier spectra were also measured at ?70°C with resolution 0.22 cm^?1 between 450 and 330 cm^?1. The K structure of the fundamentals ν₅, ν₆, ν₈, and ν₉ was assigned. These fundamentals are coupled by a-axis Coriolis interactions. These couplings were analysed on the symmetric top basis for setting up the perturbation matrix and by utilizing the K-dependent Coriolis shifts of levels. A preliminary analysis of the Coriolis intensity anomalies was also undertaken.Band center values from combination differences are $\text{ν}{}_5{}^0\text{= 587.30 (27)}$ and $\text{ν}{}_6{}^0\text{= 528.36 (39)}\text{cm}{}^{\mathrm{?1}}$. Synthetic spectra indicate the band origins of ν₈ and ν₉ to be close to 977.8 and 439.0 cm^?1, respectively. Estimates of Coriolis coupling constants obtained from synthetic spectra are $\text{ζ}{}_{58}{}^{\mathrm{a}}\text{= + 0.33 (5)}$, $\text{ζ}{}_{68}{}^{\mathrm{a}}\text{= + 0.714 (20)}$, $\text{ζ}{}_{59}{}^{\mathrm{a}}\text{= ? 0.774 (20)}$, and $\text{ζ}{}_{69}{}^{\mathrm{a}}\text{= ? 0.30 (2)}$. Approximate ratios of unperturbed vibrational transition moments obtained from spectral simulations are $\text{M}{}_8{}^0\text{:±iM}{}_5{}^0\text{:±iM}{}_6{}^0\text{:M}{}_9{}^0\text{≈ +2:?9:+10:+0.5}$.     

Long-lived non-equilibrium population of Fe3+ electronic states after the K-capture of 57Co

Mössbauer emission spectra of a frozen aqueous solution of ⁵⁷CoCl₂ show contributions from the $\text{S}{}_{\mathrm{z}}\text{= +}\text{5}\text{2}$ and the $\text{S}{}_{\mathrm{z}}\text{= +}\text{3}\text{2}$ Zeeman levels of Fe³⁺ ions at T = 4.2 K in H ? 30 kG. The K-capture results in a non-equilibrium state of relaxation time comparable to the lifetime of the nuclear excited state (～ 10^?7 s).     

Measurement of the background energy content of Nd-glass picosecond pulses with saturable absorbers

The background energy content of a mode-locked Nd-glass laser is determined with photodetectors and saturable absorbers. By comparing the signal height of a fast detector with the readout of an integrating energy meter the noise energy E_u2 outside the rise-time of the fast detector is measured. The background energy E_u1 within the rise-time is analysed by transmission measurements through two subsequent absorber cells. The obtained mean background to pulse energy (and intensity) ratios of ( and indicate a high degree of mode-locking.     

Electromigration in tin single crystals

Atom transport in high-purity tin single crystals due to the influence of large direct currents has been measured by the “vacancy flux” technique. Cylindrical specimens were selected with c-axis oriented with 9° perpendicular or parallel to the direction of current flow. Rates of both longitudinal and transverse dimensional changes were used to calculate the anode-directed atom drift velocity. The results gave $\text{Z}{}^1{}_6\text{?}{}_6\text{= ?18±2}$ and $\text{z}{}^1{}_{\mathrm{\perp }}\text{?}{}_{\mathrm{\perp }}\text{= ?18 ±2}$, where Z¹ is the effective charge number and ?₆ = 0.89 and ?_⊥ = 0.54 are the estimated correlation factors in the parallel and perpendicular directions. These values for Z¹ are appreciably smaller than the results reported earlier for polycrystalline tin by Kuz'memko. The activation energies for $\text{Z}{}^1\text{?}$ agree within experimental error with those of self-diffusion.     

The critical behaviour of spontaneous magnetization in the antiferromagnetic NiO

The spontaneous magnetization of the sublattice vs temperature in the antiferromagnetic NiO was measured by the neutron diffraction method. Temperature changes of the Bragg peaks (111), (222), (333) and (444) with the wavelengths of neutrons $\text{λ}{}_{\mathrm{I}}\text{= 4.16}\text{A}\text{?}$, $\text{λ}{}_{\mathrm{II}}\text{= 2.08}\text{A}\text{?}$, $\text{λ}{}_{\mathrm{III}}\text{= 1.39}\text{A}\text{?}$ and $\text{λ}{}_{\mathrm{IV}}\text{= 1.04}\text{A}\text{?}$, respectively were simultaneously investigated by the neutron time-of-flight spectrometer. On the basis of these measurements, the transition temperature from the antiferromagnetic into the paramagnetic phase was determined, T_N = (523 ± 1)°K. The temperature function of the (111) magnetic peak intensity has been accepted to be I ～ (T_N?T)^2β. According to the present measurements the critical point exponent is 0.33 ± ^0.02_0.04.     

Phenomenological predictions of the SO(10) supersymmetric grand unified model

The phenomenological predictions of the SO(10) supersymmetric grand unified model (SO(10) SGUM) for the mass scales M₁, M₂, weak angle ifsin²θ_w, quark-leptons mass ratios $\text{m}{}_{\mathrm{<mtext>b</mtext>}}\text{m}{}_{\mathrm{\tau }}$, $\text{m}{}_{\mathrm{t}}\text{m}{}_{\mathrm{<mtext>b</mtext>}}$, $\text{m}{}_{\mathrm{\tau }}\text{m}{}_{\mathrm{\nu }}{}_{\mathrm{\tau }}$ and proton lifetime τ_p are estimated by using renormalization group analysis at one-loop level. In contrast with SU(5) SGUM, we find that the SO(10) SGUM still has problems with τ_p but not with sin²θ_w and $\text{m}{}_{\mathrm{<mtext>b</mtext>}}\text{m}{}_{\mathrm{\tau }}$, which may suggest that supersymmetry would be bro at a mass scale $\text{?10}{}^7\text{GeV}$.     

Observation of proton emission following thermal neutron capture in 34.5 d 84Rb

Using a target prepared by on-line isotope separation, thermal neutron capture in ⁸⁴Rb (I^π = 2^?) has been shown to induce proton emission to the ground state (0⁺) and first excited state (2⁺) of ⁸⁴Kr. The branching ratio was measured as $\text{Γ}{}_{\mathrm{<mtext>p</mtext>}}\text{(0}{}^{\mathrm{+}}\text{)}\text{Γ}{}_{\mathrm{<mtext>p</mtext>}}\text{(2}{}^{\mathrm{+}}\text{)}\text{= 4.7 ± 0.7}$, favouring a $\text{3}\text{2}{}^{\mathrm{?}}$ assignment of the capturing state without excluding $\text{5}\text{2}{}^{\mathrm{?}}$, and the (n_th, p) cross section as 12 ± 2 b. The energy available for the process was determined to be 3.45 ± 0.01 MeV, in agreement with other mass data in the region.     

Pressure dependence of superconductivity in the pseudo-one-dimensional compound Tl2Mo6Se6

Measurements of the temperature and pressure dependences of the resistivity of the pseudo-one-dimensional ternary compound Tl₂Mo₆Se₆ are presented. We find that the conductivity parallel to the highly conducting c-axis is enhanced by pressure and the superconducting transition temperature T_c is suppressed by pressure at a rate $\text{?T}{}_{\mathrm{c}}\text{?P}\text{=?7.6×10}{}^{\mathrm{?5}}$ kbar^?1. These results are discussed in relation to the current models of transport in one-dimensional conductors.     

The 5T2g → 5Eg absorption in MgO: Fe2+

At helium temperatures two sharp lines at 9350 and 9510 cm^?1 have been observed for the first tune on the low-energy side of the broad double-peaked absorption corresponding to the ${}^5\text{T}{}_{\mathrm{2g}}\text{→}{}^5\text{E}{}_{\mathrm{g}}$ transition in Fe²⁺ at the octahedral site in MgO. The lower energy line has a half width of 4 cm^?1; Zeeman measurements show that it is of magnetic dipole origin. The Zeeman spectra are consistent with those expected for a pure electronic transition from the (⁵T_2g)T_2g ground state to the ⁵E_g excited state. The second line, with a halfwidth of ~ 35 cm^?1, a vibrational sideband.     

Stark mixing spectroscopy in cesium

We present a new technique for selectively populating excited states which are inaccessible by dipole excitation from the ground state. The method uses a static electric field to introduce a component of a dipole-allowed state into the state of interest. We have applied the method to cesium to measure lifetimes and a Stark mixing coefficient. The results are $\text{τ(6}{}^2\text{D}{}_{\mathrm{<mtext>5</mtext><mtext>2</mtext>}}\text{)=64(2) ns}$, $\text{τ(7}{}^2\text{D}{}_{\mathrm{<mtext>5</mtext><mtext>2</mtext>}}\text{)=92.5(15) ns}$, and <6²D_{$\text{5}\text{2}$}|;ez |7²P_{$\text{3}\text{2}$}>/(E_7P?E_6D)=0.7(3)×10^?3 where is in kV/cm. 141