[en] Newly calculated radiative transition probabilities for the B ¹Pi→X ¹Σ⁺ and A ¹Σ⁺ emission bands of ⁷LiH (preceding paper) are used to calculate the radiative lifetime of the various vibrational levels (0< or =v'< or =2) of B ¹Pi LiH. An estimate of the B→X bound--free emission probability is also included, although the lifetimes are dominated by the B→X bound--bound emission. The calculated radiative lifetimes increase rapidly with v' from 11.3 nsec at v'=0 to 17.0 nsec at v'=1 and then 24.0 nsec at v'=2

[en] The total photoionization cross section of the 1s level of nitrogen in N₂ and N₂O molecules has been measured using monochromatized synchrotron radiation. High-resolution spectra in the range 390 < h ω < 450 eV were recorded. A broadband in the continuum at 9.4 eV above the ionization threshold, due to the f-type shape resonance, has been measured with high resolution. The data are compared with theoretical calculations of photoionization cross section. Recent Hartree-Fock calculations in the static-exchange approximation agree better than earlier results, which employed the multiple-scattering method

[en] Fundamental T (ν₃) type high-J rovibrational fine structure is derived for a range of values of the Coriolis and [2 x 2]⁴ centrifugal constants. The theory of level clusters is developed further. Correlations are made between cluster states corresponding to well separated P⁺, Q⁰, and R^- branches, and the opposite case in which Pi/sub plus-or-minus/ and Σ₀ labels are appropriate

[en] We have calculated the photoionization cross section for the (1s²2s²2p⁵3s)³P metastable state of neon using ab initio, many-electron wave functions in the LS-coupling scheme. We have considered all the channels which arise from the (1s²2s²2p⁵)²P state of Ne⁺ and an ejected p electron. The continuum was made discrete by approximating the final states as superpositions of square-integrable configurations. The Stieltjes moment-theory technique was used to construct the continuum oscillator strength distribution. Both the dipole-length and the dipole-velocity forms of the cross section were evaluated. We have examined systematically the effects of orbital relaxation, core polarization, and electron correlation and found them to be important within 5 eV of threshold. The peak value of the photoionization cross section for metastable Ne is 1.9 x 10^-19 cm², which is much smaller than the corresponding value for the ground state. We have also calculated the line strengths for a few bound-bound transitions as well as the static polarizability of the ³P metastable state

[en] Multiphoton dissociation of various halogenated hydrocarbons by laser beams is reported. The statistical theory of unimolecular reactive is found to be adequate to explain the process

[en] N₂ and O₂ broadened linewidths of HNO₃ at 300⁰K have been computed for about 1500 transitions of a- and c-type and for about 2500 transitions of b-type

[en] A knowledge of the properties of small metal particles is essential to the understanding of catalysis on a molecular level. In this regard, one particularly important property is the rate at which the dissociation energy of a small metal cluster approaches the bulk cohesive energy. The present research concerns the effect of electron correlation on the dissociation energy of a particularly stable beryllium cluster, the tetrahedral Be₄ system. A contracted Gaussian basis set of size Be(9s 4p/5s 2p) was adopted in conjunction with the recently developed theory of self-consistent electron pairs (SCEP). Several new theoretical and computational wrinkles are discussed, including the incorporation of the SCEP/coupled electron pair approximation (SCEP/CEPA). The Be₄ results provide strong evidence for the reliability of the Hartree--Fock approximation for alkaline earth cohesive energies. As suggested earlier the Be₄ dissociation energy appears to be approx.40 kcal/mole. Analogous studies of the Be₂ molecule are reported

No abstract available

[en] The A--X band of gaseous UF₆ has been studied using the laser-induced fluorescence technique. Excitation and fluorescence spectra are presented for various pressures of UH₆ at room temperature. The fluorescence spectra show little change over the pressure range 0.2--20 torr, with a peak wavelength at 421 nm. In contrast, the peak wavelength of the excitation spectra shows a noticeable shift from 391 to 385 nm when the UF₆ pressure is increased from 2 to 20 torr. A Stern--Volmer plot of UF₆ self-quenching data shows a pronounced nonlinear behavior over this same pressure region. From an analysis of the laser-induced fluorescence spectra, we develop a simple kinetic model for UF₆ excited- state dynamics. A standard kinetic treatment of this scheme yields a prediction for the dependence of the fluorescence decay lifetime on total pressure that is in good agreement with experimental results

[en] A remarkable improvement of both intelligibility and naturalness of infinitely clipped speech can be achieved by means of a multichannel system in which the speech signal is splitted into several band-pass channels before the clipping and successively reconstructed by summing up the clipped outputs of each channel. A possible explanation of such an improvement is given, founded on the so-called zero-based representation of band limited signals where the zero-crossings sequence is considered as a set of samples of the signal