Brillouin study of acoustic phonon softening and optical absorption coefficients of ultraheavily doped n-Si

The self-energies of acoustic phonons in ion implanted and laser annealed ultraheavily doped n-type Si have been measured by Brillouin scattering. The corresponding softening of the elastic constants has been estimated from the observed phonon softening and compared it with theory. At high doping levels ($\text{N}{}_{\mathrm{e}}\text{≧ 10}{}^{21}\text{cm}{}^{-3}$) the effect of the increase in atomic mass on the phonon frequency is observed in the case of doping with As. From the increase in the linewidths of the Brillouin lines with doping, the optical absorption coefficients for $\text{λ = 5145}\text{A}\text{?}$ as a function of doping are determined.     

Studies of interface phonons

The vibrational modes localized at the interface between two distinct crystals have been studied for a simple crystal model obeying all of the invariance conditions required for models used in studies of dynamical properties of crystal surfaces, and giving rise to Rayleigh surface waves. The two crystals are assumed to be semi-infinite simple cubic and to have the same lattice parameter a. They differ by their mass (M and M_A) and the central force interactions between first (K and K_a) and second nearest neighbors $\text{1}\text{2}\text{K}$ and $\text{1}\text{2}\text{K}{}_{\mathrm{A}}$. The interface is obtained by coupling the (001) free surfaces of these distinct crystals by central force intractions (K^'). We find that the variation of the interaction conditions (K^') at the interface and of the $\text{(}\text{K}\text{M}\text{)}\text{(}\text{K}{}_{\mathrm{A}}\text{M}{}_{\mathrm{A}}\text{)}$ parameter has the following qualitative effects on the properties of surface and bulk phonons. When (K^') increases from zero to a finite value, the frequencies of the surface phonons increase and are splitted in the case of two identical crystals. One can say that the surface phonons are transformed into interface modes. For some values of $\text{K}{}^{\mathrm{\text{'}}}\text{K}$ and $\text{(}\text{K}\text{M}\text{)}\text{(}\text{K}{}_{\mathrm{<mtext>A</mtext>}}\text{M}{}_{\mathrm{<mtext>A</mtext>}}\text{)}$ parameters these interface phonons may be admixed with bulk phonons and thus become virtual interface states.     

A valence quark model for large pT pion production

A hard scattering mechanism for the production of large p_T hadrons is suggested which only involves valence quarks. The corresponding $\text{π}{}^{\mathrm{+}}\text{π}{}^{\mathrm{?}}$ ratio and the ratios of the away side charged pion correlations are in satisfactory agreement with data.     

Absorptive parts of the hadron-nucleus amplitude and multiparticle production on nuclei

The process of the hadron-nucleus interaction is considered in the framework of Glauber theory. A two-channel model is used for inelastic shadow corrections due to low-mass diffractive jets. It is shown that inelastic hadron-nucleus cross sections are connected with the cuts of a number of hadron-nucleon blobs in the elastic scattering amplitude. The relations derived between contributions to the absorptive part of the amplitude from cuts of different kinds satisfy the Abramovsky-Gribov-Kancheli rules up to a factor which is determined by the ratio of the inelastic and total hadron-nucleon cross sections. The inclusive spectrum in the central region is proportional to $\text{A}{}^{\mathrm{<mtext>1</mtext><mtext>3</mtext>}}$. The average charged multiplicity increases with A slower than $\text{A}{}^{\mathrm{<mtext>1</mtext><mtext>3</mtext>}}$ due to energy conservation. The results obtained are in good agreement with experimental data on the average multiplicities and distributions of charged particles.     

Inclusive hadron-nucleus scattering at high energy

The multiple scattering series of Glauber and Matthiae for hadron-nucleus scattering is summed to a simple analytical expression. It reproduces quantitatively the main features of the experimental cross section for the reaction ${}^4\text{He}\text{+}{}^{\mathrm{A}}\text{Z →}{}^4\text{He + X}$ at 1 GeV/nucleon.     

Homogeneously broadened far-infrared absorption line due to the E → 2A transition of excited chromium ions in ruby

By use of far-infrared laser spectroscopy, we have found that for a high-quality ruby crystal at low temperature, the absorption line due to the electronic transition between the excited states $\text{E}\text{(}{}^2\text{E)}$ and $\text{2}\text{A}\text{(}{}^2\text{E) of Cr}{}^{\mathrm{3+}}$ ions is homogeneously broadened. From the linewidth (0.011 cm^-1) the lifetime of the 2ā level against emission of 29 cm^-1 phonons is obtained.     

Electrodisintegration of 3He

Double differential cross sections for electron-³He scattering leading to continuum states were measured between break-up threshold and the region of quasi-free interaction in a momentum transfer range of $\text{1}\text{fm}{}^{\mathrm{?2}}\text{< ¦}\text{q}\text{¦}{}^2\text{< 2.5}\text{fm}{}^{\mathrm{?2}}$. The cross sections for the quasi-free scattering calculated in plane-wave impulse approximation were found to be in good agreement with the experimental results for momentum transfer $\text{¦}\text{q}\text{¦ > 1.5}\text{fm}{}^{\mathrm{?1}}$.     

Charge properties of the hadronic system in vp and νp interactions

Charge properties of the hadronic systems from νp and $\text{ν}\text{p}$ scattering in BEBC are studied in the framework of the quark-parto model (QPM). The average charges $\text{〈Q}{}_{\mathrm{<mtext>jet</mtext>}}\text{〈}{}^{\mathrm{<mtext>\nu </mtext>}}$ and $\text{〈Q}{}_{\mathrm{<mtext>jet</mtext>}}\text{〈}{}^{\mathrm{<mtext>\nu </mtext>}}$ of a quark jet and a d-qua jet, respectively, are determined according to two different methods. The difference $\text{〈Q}{}_{\mathrm{<mtext>jet</mtext>}}\text{〈}{}^{\mathrm{\nu }}\text{? 〈Q}{}_{\mathrm{<mtext>jet</mtext>}}\text{〈}{}^{\mathrm{<mtext>\nu </mtext>}}$ is in agreement with e QPM value of 1. Scaling of charge and energy flow in the angular variable λ is demonstrated. The ratios $\text{ΔQ}{}^{\mathrm{<mtext>\nu </mtext>}}\text{/ΔQ}{}^{\mathrm{\nu }}$ of charge flows in νp a $\text{ν}\text{p}$ scattering are in accord with the QPM in both hemispheres.     

Shell model calculations of inelastic electron scattering from 51V and effective charges

Form factors for inelastic electron scattering for the excitation of the $\text{3}\text{2}{}^{\mathrm{?}}$, $\text{5}\text{2}{}^{\mathrm{?}}$, $\text{9}\text{2}{}^{\mathrm{?}}$, $\text{11}\text{2}{}^{\mathrm{?}}$ and $\text{15}\text{2}{}^{\mathrm{?}}$ members of the ($\text{f}{}_{\mathrm{<mtext>7</mtext><mtext>2</mtext>}}\text{)}{}^3$ configuration in ⁵¹V are studied by considering the effect of configuration mixing in the shell model. The inclusion of the highly excited configurations which does not contribute to the γ-transitions is shown to give rise to significant modifications of the form factors in large momentum transfer regions. Under the assumption of the static central potential as the residual interactions between protons, good agreement with the experimental data on form factors is obtained by the ordinary force as well as smaller effective charges than the bare charge for higher multipole transitions.     

Multistep transfer processes in inelastic heavy ion reactions

Multistep transfer contributions in inelastic heavy ion scattering are investigated in a coupled channels model for the reaction ${}^{17}\text{O}\text{(}{}^{16}\text{O}\text{,}{}^{16}\text{O}\text{)}{}^{17}\text{O}\text{(}\text{1}\text{2}{}^{\mathrm{+}}\text{, 0.871}\text{MeV}\text{)}$. We find that only the interference of the one- and two-step transfer contributions gives agreement with recent experimental results. This is interpreted as strong evidence for multistep processes in heavy ion scattering.     

65 MeV polarized proton elastic scattering and the effective two-body interaction range

Elastic scattering of polarized protons from sd and fp shell nuclei has been studied with high-purity germanium detectors. The mean square radius of the central real part of the fitted optical potential was found to be of the form $\text{a}\text{+}\text{bA}{}^{\mathrm{<mtext>2</mtext><mtext>3</mtext>}}$. Comparison with the radius from electron scattering gives the range of the effective two-body interaction and its A dependence as $\text{〈}\text{r}{}^2\text{〉}{}_{\mathrm{d}}\text{=(4.5±0.4)+(0.16±0.03)}\text{A}{}^{\mathrm{<mtext>2</mtext><mtext>3</mtext>}}\text{fm}{}^2$.     

The phase anomaly for elastic and inelastic scattering of the 19F + 12C system

The elastic and inelastic scattering of ¹²C from ¹⁹F leading to the $\text{1}\text{2}{}^{\mathrm{+}}\text{(}\text{gs}\text{),}\text{5}\text{2}{}^{\mathrm{+}}\text{(197}\text{keV}\text{),}\text{3}\text{2}{}^{\mathrm{+}}\text{(1.554}\text{MeV}\text{)}$ and $\text{9}\text{2}{}^{\mathrm{+}}\text{(2.780}\text{MeV}$) states has been studied at $\text{E(}{}^{12}\text{C}\text{)=30?60}\text{MeV}$. The angular distributions for the $\text{5}\text{2}{}^{\mathrm{+}}\text{and}\text{3}\text{2}{}^{\mathrm{+}}$ transitions are almost in phase with those of the elastic scattering and cannot be reproduced with the DWBA and CC caculation using collective form factors.     

Measurement of coherent pion-photoproduction on the 3He/3H isodoublet

Neutral and charged pion-photo production on ${}^3\text{H}$ and ${}^3\text{He}$ nuclei have been observed in the Δ(1232) resonance region. Resonance averaged cross-sections are presented as functions of momentum transfer.     

Right-handed weak currents in neutrino scattering

We investigate transition strengths of right-handed weak charged currents in deep inelastic neutrino scattering, exploiting the dominance of p, n valence quarks in the nucleon. The energy dependence of σ_t and the average quantities 〈y〉 and 〈Q²〉 are shown to provide sensitive measures of new quark production thresholds and right-handed currents in $\text{ν}\text{N}$ scattering. With our analysis, the present data give an upper bound on the right to left hand structure function ratio of $\text{F}{}_{\mathrm{<mtext>R</mtext>}}{}^{\mathrm{<mtext>\nu </mtext><mtext>N</mtext>}}\text{F}{}_{\mathrm{<mtext>L</mtext>}}{}^{\mathrm{<mtext>\nu </mtext><mtext>N</mtext>}}\text{≈}\text{1}\text{2}$, above a threshold of W≈7.5 GeV.     

Decay amplitudes of the 208Pb(0+) analogue resonance

Measurements were made of elastic and inelastic proton scattering on ²⁰⁷Pb targets in the energy range from 11.1 to 14.4 MeV. The scattering to the $\text{1}\text{2}{}^{\mathrm{?}}$ ground state and to the $\text{3}\text{2}{}^{\mathrm{?}}$ and $\text{5}\text{2}{}^{\mathrm{?}}$ exciced levels was analyzed in terms of a 0⁺ analogue resonance interfering with the non-resonant background and with the contribution from the 3^? resonance. The resonance parameters were determined together with the magnitude and relative sign of three background components.     

Search for heavy particles in cosmic rays

A search for heavy, long-lived particles has been made in the cosmic rays. The observations may possibly be explained in terms of known particles, but they appear to be more easily explained in terms of a flux $\text{? 6.10}{}^{\mathrm{?9}}\text{cm}{}^{\mathrm{?2}}\text{sec}{}^{\mathrm{?1}}\text{sr}{}^{\mathrm{?1}}$ if singly charged particles having mass $\text{? 6 m}{}_{\mathrm{<mtext>p</mtext>}}$.     

Localized modes and central peak at displacive phase transitions

The influence of defects, which raise locally the transition temperature, on structural transitions is studied. At the local transition temperature $\text{T}{}^{\mathrm{<mtext>l</mtext>}}{}_{\mathrm{c}}$ a localized phonon condenses. The resulting cluster couples linearly to the band phonons and gives a central peak.     

Electronic spectra of azanaphthalenes: Solid state spectra of cinnoline and quinazoline

The first electronic absorption region ($\text{π}{}^1\text{← n}$) of cinnoline has been measured in durene and naphthalene as host crystals at 4 K and of quinazoline likewise in durene, naphthalene, and the pure crystal. The $\text{π}{}^1\text{← n}$ region is analyzed as a single transition in both cases in agreement with prior vapor studies, but all the spectra are complicated by the presence of at least two inequivalent sites with site splittings as large as 450 cm^?1. In one instance (quinazoline in naphthalene) polarization ratios permit the conclusion that the two observed site spectra correspond to the two alternative placements of the guest molecule in a vacancy in the host lattice. Site and host dependent effects are documented on phonon activity, vibrational frequencies, polarization ratios, and the incidence of vibronic (Herzberg-Teller) activity.The salient properties of the first $\text{π}{}^1\text{← π}$ absorptions of both molecules and of the $\text{π}{}^1\text{→ π}$ phosphorescence of quinazoline are briefly noted.     

Alpha-particle scattering from 9Be

The elastic and inelastic scatterings of 35.5 MeV ⁴He ions from ⁹Be are analyzed in the strong coupling limit by the coupled channel method. A good account of the ground-state ($\text{K =}\text{3}\text{2}{}^{\mathrm{?}}$) band is obtained, in agreement with the electromagnetic properties of this band. Data for three states of the $\text{K =}\text{1}\text{2}{}^{\mathrm{+}}$ band are analyzed, yielding much larger isoscalar dipole scattering amplitudes for the $\text{3}\text{2}{}^{\mathrm{+}}$ state than are obtained by electron scattering for electric dipole transitions.