Nonideal Plasma Generation by Mechanical Compression

Nonideal plasmas have been generated by mechanical compression with a so-called ballistic compressor. The Debye numbers reached were 0.4 in argon and 0.2 in xenon. The experimentally determined pressure, specific volume, and temperature are compared with calculations of the compression using different models of the charged particle interaction. This comparison shows that heat losses may take an essential part in the interpretation of the experimental results.     

Collisional radiative model of helium including response to resonant radiation

A collisional-radiative model of helium has been developed that incorporates the effect of optical pumping with light that is resonant with an atomic transition. A steady-state solution of the collisional- radiative model with no pumping is used as an initial condition. The pumping radiation is switched on, and the population densities of the atomic levels are calculated as a function of time. Results are given for a wide range of plasma parameters and various pumping conditions.     

The dipole moment derivatives and charge flux parameters from vibrational absorption intensities of ethylene oxide

The signs of dipole moment derivatives for ethylene oxide obtained from ab initio calculations using the 6-31G¹ basis set are presented. From these signs and the experimental vibrational absorption intensity data, the atomic polar tensor elements and bond charge flux parameters were evaluated. These quantities were compared with those in the literature calculations employing approximate signs and force constants.     

Effects of flanking noise bands on the rate of growth of loudness of tones in normal and recruiting ears

Five subjects with unilateral cochlear hearing impairments and three normally hearing subjects made loudness matches between tones presented alternately to two ears, as a function of the intensity of the tone in the impaired ear (or the left ear of the normal subjects). The impaired ears showed recruitment; the rate of growth of loudness with increasing intensity was more rapid in the impaired ear than the normal ear. Presenting the tone in the impaired ear with two noise bands on either side of the tone frequency, at a fixed signal-to-noise ratio, did not abolish the recruitment. This suggests that recruitment is not caused by an abnormally rapid spread of excitation in the peripheral auditory system. At low signal-to-noise ratios, a continuous background noise reduced the loudness of the tone more than a noise gated with the tone, suggesting that the continuous noise induces adaptation to the tone. The noise had a greater effect on the loudness of the tone in normal ears than in impaired ears. It is possible that the loudness reduction of the tone in noise is mediated by suppression; suppression is weak or absent in impaired ears, and so the loudness reduction is smaller.     

Die Kristall- und Molekülstruktur des dimeren Dimethylaminodimethylindiums

Crystal and Molecular Structure of Dimeric Dimethylaminodimethylindium Dimeric dimethylamino-dimethylindium was prepared by splitting off methane from the adduct Me₃In? NHMe₂ and characterized by its vibrational spectra. The structure – determined by X-ray analysis – has shown to have the monoclinic space group P2₁/c with a = 7.601, b = 7.336, c = 14.927 Å and β = 119.9°. Patterson, Fourier and Difference synthesis were used for determing the structure, which was refined by least square analysis to an R value of 0.068.     

Vibrational energy transfer according to the morse potential: Application to self-relaxation of methane

The perturbation integral in the semiclassical theory of vibrational energy transfer is derived in closed form for a Morse potential. The temperature dependence of VT tranfer in CH₄CH₄ collisions is investigated, using a recently published numerical CH₄ potential to determine the parameters of the Morse potential.     

Zum Einfluß der intermolekularen Wechselwirkung auf den Depolarisationsgrad von Ramanlinien

A perturbation calculation is used to determine the effect of intermolecular interactions on the depolarization ratio of Raman lines. For highly polarized Raman lines an approximate formula is given, which enables the evaluation of the relative change of the anisotropy scattering using the change in the degree of depolarization.