Showing papers in "Chemical Physics in 1974"

TL;DR: In this article, the electron transfer reaction within a donor-acceptor, solvent separated ion pair (2A++2D·−) leading to excited singlet, excited triplet, and ground state products is studied within the framework of the theory of nonradiative transitions.

TL;DR: In this paper, the authors consider the kinetics of a reaction in a polymer system where each reacted unit protects its (r − 1)-nearest neighbours completely against reaction and modifies the reactivity of the r − 1 nearest neighbours.

TL;DR: In this paper, the vibrational relaxation of gaseous H2 in mixtures with He, Ne, Ar, and Kr was studied by the laser Schlieren technique in incidents shock waves at 1350-3000 K.

TL;DR: In this paper, absolute emission cross sections and threshold energies have been measured for radiation from excited fragments (OH, O and H) produced by electron impact (0-1000 eV) on water vapour.

TL;DR: In this article, the effect of molecular motion on NMR powder spectra governed by axially symmetric shielding tensors is investigated, and the results show that at low temperatures the powder pattern for a rigid solid is observed, from which we obtain the shielding anisotrophy Δσ = σ − σ⊥ = −405 ± 10 ppm.

TL;DR: In this article, the intermolecular potentials for D2, N2, O2, F2 and CO2 are determined on the basis of the second virial coeffincients, the polarizabilities parallel and perpendicular to the molecular axes, and the electric quadrupole moment.

TL;DR: In this paper, the influence of intermolecular vibrational relaxation on dipole moment correlation functions, as obtained from IR band shapes, is discussed, and the implications for various procedures used to “correct” Raman and IR band shape for vibrational relaxations are discussed.

TL;DR: The geometry of the biphenyl molecule has been studied with the MO LCAO method using a gausian basis set of double zeta quality as discussed by the authors, and the lowest energy has been obtained for a non-planar conformation having a twist angle of 32°.

TL;DR: In this paper, the authors derived an explicit expression for the time dependence of the resonant interaction of lorentzian photons with molecular systems using scattering theory and discussed the dependence of molecular states on the nature of the exciting photon with an additional regard for the appropriate choice of basis sets.

TL;DR: In this paper, a nanosecond laser spectrometer consisting of a 3nsec ruby/Nd PTM laser, fast detection system and high brightness analysing source is described.

TL;DR: In this article, a zero-order density function is derived from the observed spectrum, allowing the spectroscopic analysis to be continued from the weakly perturbed region into the strongly pertubed resonance.

TL;DR: In this paper, the decay process of qua- si-isolated molecules is studied in the case of strong coupling, where the effects of regularities in the level spacing and the distribution of the oscillator strength in the manifold determine the long time behavior.

TL;DR: In this paper, a theory of radiationless transitions that spans the intermediate case between the small molecule and big molecule limits is presented, which is applicable to spectra and picosecond time evolution experiments concerning states such as the vibronically perturbed second excited single state of naphtalene studied by Wessel.

TL;DR: In this paper, the final state distributions for inelastic collisions of I * 2 with rare gas atoms are analyzed with the recently introduced surprisal function, and experimental data and classical trajectory results are compared.

TL;DR: In this paper, the four main bands of the spectra of butatriene (I), tetradeuterobutatriene(II), tetramethylbutatriene, III and tetra-t -butyl-butylbutyl butatrienes (IV) are reported and discussed.

TL;DR: The classical S matrix theory developed by Miller and Marcus is applied to the collinear H + H2 reaction on a model potential energy surface in this article, where the classical, primitive, and uniform approximations and the initial value representation integral expression for the S matrix are calculated for total energies in the range 15-30 kcal/mole and compared to the exact quantum mechardeal calculations of Diestler.

TL;DR: In this article, the lifetime and time resolved fluorescence spectra of standard compounds (quinine sulfate and fluorescein anion) were measured and compared to those of conventional “nanosecond” flash lamps.

TL;DR: In this article, the behavior of single vibronic level non-radiative decay rates in benzene and benzene- d 6 were investigated in detail, and the effects of excitation in a promoting mode which undergoes frequency and geometry changes in the S 1 relaxation (to T 1 or S 0 ) were considered in detail.

TL;DR: In this article, the Boltzmann law was used to analyze the spectral changes of the charge transfer photoluminescence of the title compound between 2 and 10°K.

TL;DR: In this article, the authors studied the dissociative excitation of acetylene by determining the emission cross sections of the excited fragments (CH, C2, H and C) as a function of the electron impact energy (0-1000eV).

TL;DR: In this paper, the Monte Carlo method was used to evaluate the reaction field strength and the Kirkwood structure factor in a fluid of hard cores with central embedded point dipoles, and the long ranged interactions were computed by a crystallographic method.

TL;DR: In this paper, different methods for representing the upper orbitals in Rydberg transitions are tested by means of a series of ab initio SCF and CI calculations for ethylene and various properties for such diffuse united-atom species are reported.

TL;DR: In this article, the reaction of hydrated positrons with cloride ions in aqueous solutions was studied by means of positron annihilation angular correlation measurements, and a rate constant of k = (2.5 ± 0.5) × 10 10 M −1 s −1 was found.

TL;DR: In this article, the excitation and emission spectra and decay times of several MnX 2-4 (X = Cl −, Br −, 1 − ) complexes of various tetraalkylammonium, -phosphonium, and -arsonium salts have been measured for the pure solids at 298°K and 77°K.

TL;DR: In this article, the importance of long range tunneling in electron transfer reactions in condensed media is discussed, and the factors determining the efficiency of tunneling, as well as some peculiar features of tunnel-ing kinetics are considered.

TL;DR: In this paper, the authors studied the 13C resonance of the carbonyl and carboxyl carbons in the compounds listed in the title and determined the complete shielding tensor σ from a single crystal study.

TL;DR: In this article, the mass spectra of the resulting H + or D + fragments are recorded with a mass spectrometer and the excess kinetic energy is calculated from the spectra.

TL;DR: In this paper, the electronic wavefunctions for the ground (X1 Σ+) and the low-lying excited states (a3Π, A1Π and 3Σ+) of the BH molecule have been calculated as a function of internuclear distance using the ab initio generalized valence bond method (GVB) with optimization of spin coupling (SOGI).

TL;DR: In this article, the surface potential of Xe appears to be directly related to the heat of adsorption: a large heat of adaption is accompanied by a large surface potential.

TL;DR: In this article, the elastic scattering of atoms from solid surfaces is examined within the semiclassical framework and explicit expression for diffraction intensities are obtained which utilize classical trajectory information as the computational device.