Showing papers in "Chemical Physics in 1975"

TL;DR: In this paper, the effect of the muffin-tin approximation, and of an approximation which involves a spherical averaging procedure, upon the ionization potentials and charge distribution is assessed by a comparison with accurate calculations.

TL;DR: In this paper, a theory of molecular vibrations is presented which is based upon the Morse, as opposed to the harmonic oscillator, and the stretching overtone spectra of the benzene and water molecules have been calculated, these examples being chosen on account of the high degree of anharmonicity characterizing their potentials and the availability of suitable experimental data.

TL;DR: In this paper, an analysis is made of diffusion-controlled ring closure reaction of a polymer chain based on the general theory of Wilemski and Fixman, and it is shown that the reaction rate is strongly affected by the short time behavior of the segmental motion, and consequently the harmonic spring model and the Rouse model yield quite different results.

TL;DR: In this article, two interacting HF and CH 2 O molecules have been treated at medium (3.20 A) intermolecular distances at one common supermolecule using the ab initio SCF LCAO MO method, and their interaction energies have also been calculated with the aid of a perturbational scheme of Murrell.

TL;DR: In this paper, it was shown that collision dynamics are described by the two electronic potential energy surfaces which correlate with the electronically degenerate Λ components (doublets) in the diatomic molecule.

TL;DR: In this paper, the valence ionization potential of pyridine and phosphoridine is studied by an ab initio many-body approach which includes the effects of electron correlation and reorganization beyond the Hartree-Fock approximation.

TL;DR: In this paper, the infrared absorption of C 2 H 2 in a mild discharge through argon trapped at 14 K was used for determination of the stretching and stretching-interaction force constants of HC 2, which have permitted estimates of the bond lengths.

TL;DR: In this paper, the decay of NO has been studied by single photon counting using the synchrotron radiation from the Orsay Electron Storage Ring (ACO) as a source of excitation.

TL;DR: In this paper, the potential surfaces for ground and excited states (below 11 eV) of acetylene are computed with an ab initio frozen core method. Various planar and non-planar geometrics are investigated.

TL;DR: In this article, the PMR signals of each individual proton species present in water-ethanol mixtures were analyzed throughout the entire range of composition, and the experimental results were discussed in terms of possible mechanisms of molecular aggregation in the various regions of ethanol concentration.

TL;DR: In this article, the repulsive part of the pair potential between the ions in liquid metals can be obtained from the structure factor curve lying beyond the first diffraction maximum, and a general form for a repulsive potential is presented.

TL;DR: In this paper, HeI and HeII excited spectra from a clean Ru(001) surface and surfaces covered with oxygen of CO1 recorded at a variety of electron take-off angles.

TL;DR: In this article, the authors analyzed the Positron lifetime spectra for aqueous solutions of NaIO 4, KMnO 4, K 2 Cr 2 O 7, and CuCl 2 to obtain lifetimes and relative intensities for the long and short-lived components which are mainly due to ortho-and para-positronium (Ps) respectively.

TL;DR: In this paper, the potential surfaces of the HCO + and COH + molecular ions in both ground and low-lying excited states were analyzed and the bonding characteristics of the two systems were undertaken, from which it was noted that the 5σ and 1π orbital energy levels in HCO+ are inverted relative to the order found in both COH+ and also in CO itself.

TL;DR: In this article, a 3D classical trajectory study of a hypothetical exothermic reaction A + BC a AB + C employing all combination of a pair of contrasting potential-energy by hypersurfaces for reaction (one predominantly repulsive and one attractive) was presented.

TL;DR: The rotational energy in collisions between N 2 and noble-gas atoms has been investigated experimentally as well as theoretically as discussed by the authors, and a definite influence of the atomic mass on the relaxation of N 2 is observed.

TL;DR: In this article, a hard sphere model of the kinetic diffusion coefficient was proposed to analyze the dynamical information contained in the kinetic coefficient in terms of a simple hard sphere theory of molecular motion.

TL;DR: In this paper, the interaction of π-electrons in [2,2] phanes was studied both experimentally and theoretically, and the results for the phanes with two identical aromatic units can be summarized as follows: the rather small reduction of the D and E values of the order of 10% with respect to the monomers indicates, in agreement with the theoretical treatment given in part II, that the two unpaired electrons of the excited triplet state have a high probability to be at a given time in the same half of the molecule.

TL;DR: In this article, Raman and infrared band shapes of some symmetric top molecules in the neat liquid and in solution were measured and used to obtain vibrational and rotational correlation functions and relaxation times.

TL;DR: In this article, the effects of neglecting electron correlation in the Hartree-Fock approximation have been investigated for selected properties of two strongly hydrogen-bonded systems, and it has been shown that accounting for correlation will substantially lower and, in some cases, remove barriers for proton transfer which have been obtained using the HFR approximation.

TL;DR: In this paper, the authors made a study of the visible chemiluminescence resulting from the reaction of an atomic beam of samarium or europium with O3, N2O, NO2 and F2 under single-collision conditions (∼10−4 torr).

TL;DR: In this article, the 2p-excitation spectra in the XUV region of argon and of the isoelectronic second row hydride molecules HCI1 H2S1 PH3 and SiH4, recently recorded by Hayes and Brown, are discussed and assigned on the absis of qualitative arguments and ab initio calculations.

TL;DR: In this article, the problem of radical pair substitution in Chemically Induced Dynamic Nuclear Polarization is reconsidered, assuming non-disturbance of the electron spin state during the scavenging reaction.

TL;DR: In this paper, the crystal structure of the 1,3-propylenediammonium chloride (POMC) and manganese chloride (MCL) is reported.

TL;DR: In this paper, a green-function method is used to calculate a photoelectron spectrum of C 2 N 2 including the vibrational structure, and the calculated spectrum and the experimental spectrum are in good agreement.

TL;DR: In this article, a general expression for the time course of the fluorescence anisotropy of chromophores rotating about a fixed axis, with an amplitude of rotation limited by two reflecting barriers.

TL;DR: The results of detailed spectroscopic experiments on the lowest nπ* triplet state of p-benzoquinone-h4, -dh3, 2,6-d2h2, -d4 and -CH3 in mixed and isotopic mixed crystals are presented and analyzed in this paper.

TL;DR: In this article, the nuclear coordinate dependence of the electronic matrix elements for radiationless transitions (in the weak coupling limit) is investigated by the use of a Q -centroid approximation.

TL;DR: In this article, the dependence of ion pair formation in collisions of fast alkali atoms (K, Na and Li) with SF6 on the initial relative kinetic energy and the internal energy of the target molecule has been studied by the crossed molecular beam method.

TL;DR: In this paper, experimental relative abundances of D 2 O +, OD + and D + ions are given as functions of the initial energy of D O + ions in the B 2 B 2 state.