Mean amplitudes of vibration and coriolis coupling constants of some XY3Z type silicon compounds

A theoretical treatment of the generalised mean-square amplitudes of vibration of some silicon compounds of XY₃Z type molecules is presented. The numerical values evaluated for the parallel and perpendicular mean-square amplitudes for all the bonded and non-bonded atom pairs are tabulated. The L matrix elements and Coriolis coefficients have also been evaluated for these molecules.     

Microscopic determination of nuclear deformation energy surfaces at very high spins

The deformation energy surfaces of a number of rare-earth nuclei are calculated microscopically as a function of the Bohr-Mottelson deformation parameters (β,γ), for the very high spin states $\text{(30}\text{h}\text{?}\text{?J?70}\text{h}\text{?}\text{)}$ and compared with semiphenomenological Strutinsky based calculations. The possibility of rotational isomers (yrast traps) is discussed.     

Absorption spectrum of carbon dioxide at 4.3 μm

The absorption spectrum of carbon dioxide has been recorded in the wavenumber region 2395-2216 cm^?1 with a spectral resolution between 0.02 and 0.03 cm^?1. About twenty transitions have been identified and the molecular constants of the levels involved have been evaluated. In view of the interest of this region in atmospheric studies a map of the entire spectrum recorded by using a normal sample of carbon dioxide is presented including the identifications for the different bands. About 90% of the lines observed have been interpreted. Some of them have been assigned to transitions originating from higher excited states of ¹²C¹⁶O₂ not considered before in interpreting this spectral region. For the first time, bands of ¹²C¹⁶O¹⁷O have been identified in the 4.3-μm spectra obtained with the natural sample.     

Pressure effects on the semiconductor-semimetal transition in Ti2O3

Hydrostatic pressure has negligible effect on the resistivity anomaly and thec _H /a _H ratio of Ti₂O₃. The results are consistent with the band-crossing mechanism wherein the a ^T and e ^T bands cross as thec _H /a _H ratio increases.     

A system of strings and springs in three dimensions

A three-dimensional array of classical strings and springs oscillating in three dimensions is investigated with combined analytical-numerical tools. The strings are continuous and linear. The long time behavior of the system changes dramatically when the springs are changed from linear to non-linear. The equipartition of energy, even among the particles, is badly violated. The power spectrum is consistent with chaotic motion. The maximal Lyapunov exponent is vanishing within our approximation. The most remarkable finding is a certain pairing of time averages for the particles, which occurs for many initial conditions in the non-linear case.     

Self-broadened widths and shifts of CO2: 4750-7000 cm

In the previous paper, we report line strength measurements for 58 bands of ¹²CO₂ between 4550 and 7000 cm⁻¹ [R.A. Toth, L.R. Brown, C.E. Miller, V. Malathy Devi, D. Chris Benner, J. Mol. Spectrosc., this issue, doi:10.1016/j.jms.2006.008.001.]. In the present study, self-broadenedwidth and self-induced pressure shift coefficients are determined in two intervals:

(a) between 4750 and 5400 cm⁻¹for bands of the Fermi triad (20011 ← 00001, 20012 ← 00001, 20013 ← 00001), three corresponding hot bands (21111 ← 01101, 21112 ← 01101, 21113 ← 01101) and the 01121← 00001 combination band;

(b) between 6100 and 7000 cm⁻¹ for the Fermi tetrad (30014 ← 00001, 30013 ← 00001, 30012 ← 00001, 30011 ← 00001), two associated hot bands (31113 ← 01101, 31112 ← 01101), as well as 00031 ← 00001 and its hot band 01131 ← 01101.

Least-squares fits of the experimental width and pressure shift coefficients are modeled using empirical expressions:

     

Low frequency electromagnetic waves in a multi-ion plasma

The dispersion characteristics of low-frequency electromagnetic waves are studied in a plasma containing hydrogen ions and positively and negatively charged oxygen ions and electrons. This composition of the plasma approximates very well the coma of comet Halley where many heavy ions have been observed in appreciable numbers. The excitation of these waves results from the relative motion between the protons and the heavy ions, which are considered unmagnetised and, therefore, may act like a beam. We find that the wave growth increases with increasing heavy ion densities, beam velocities and propagation angles.     

Vibrational relaxation study in 4-chloroacetophenone

Vibrational relaxation process has been emerged as a useful tool in probing the nature of solute solvent interactions in liquid phase. The Laser Raman techniques have been used to study the vibrational and rotational frequencies of molecules, which provide detailed information about the dynamic processes involved in liquids. Raman spectra of C=O stretching mode of 4-chloroacetophenone dissolved in acetonitrile and chlorobenzene have been recorded as a function of solvent concentration ranging from 10% to 90% concentration at room temperature. The 4-chloroacetophenone is a molecule having wide application in manufacture of drugs, perfumes and cosmetics. This study may provide useful information about the vibrational relaxation mechanisms in liquid solutions at molecular level. The Laser Raman components were determined and the spectra were analyzed at different solvent concentrations. The theoretical models have been tested and compare with the experimental results.