摘要:

Free-bound and free-free radiative absorptions by a pair of atoms are discussed and explicit formulas are derived for the free-bound and free-free absorption cross sections. The theory is applied to the interpretation of helium absorption near 600åand it is argued that the first two bands observed arise from transitions into quasibound resonating vibrational levels of theA1Σu+state. The shape of theA1Σu+potential energy curve is derived for internuclear distances between 2 and 3å. The absorption data analysis lead to a potential barrier of magnitude 0·049 ev. The effects on the absorption structure of replacing4He by3He are predicted. An iterative procedure is described that simultaneously locates the energy and evaluates the width of a quasibound-shape resonance state.

ISSN:0026-8976    

DOI:10.1080/00268977100100111

出版商:Taylor & Francis Group    

年代:1971

数据来源: Taylor

摘要:

Ab initiocalculations of the vibronic potential surface of the2T2ground state of CH4+have been carried out, using a contracted gaussian approximation to a double-zeta basis of Slater orbitals. The minimum energy is found for a tetragonal distortion to the point groupD2d, with two HCH angles of 141° and four of 96°, and allrchequal. All calculations for distorted CH4+were carried out with the meanrchheld at 1·147å, which minimises the energy forTdsymmetry. The distortion fromTdsymmetry lowers the electronic energy by 1·41 ev. Distortions fromTdtoC3vlead to a maximum stabilization of 1·22 ev. Vibronic perturbation parameters derived from this surface are employed in discussions of the2T2-1A1photoelectron transition of CH4and a possible2E←2B2absorption transition of CH4+. A vibrational interval of ∼ 1200 cm-1observed near the origin of the2T2-1A1photoelectron transition is assigned to one component ofv2(calculated frequency, 1300 cm-1).

ISSN:0026-8976    

DOI:10.1080/00268977100100121

出版商:Taylor & Francis Group    

年代:1971

数据来源: Taylor

摘要:

Infra-red and Raman selection rules are obtained for the cyclopentane molecule, on the assumption that it has a free pseudo-rotation with a large potential hump at theD5hconfiguration. The selection rules obtained, which concern the vibrational, pseudo-rotational, and rotational quantum numbers, are summarized in tables 1, 2 and 3.

ISSN:0026-8976    

DOI:10.1080/00268977100100131

出版商:Taylor & Francis Group    

年代:1971

数据来源: Taylor

摘要:

The N.M.R. spectrum ofo-chlorotoluene, dissolved in the nematic phase of 4-methoxybenzylidene-4-amino-α-methylcinnamic acidn-propylester is analysed and the shape of the proton skeleton determined. The position of lowest energy of the potential barrier to methyl rotation is found to be that in which the chlorine atom is staggered to the methyl group, and the height of the barrier is of the order of 5·0 kJ mol-1(1200 cal/mole).

ISSN:0026-8976    

DOI:10.1080/00268977100100141

出版商:Taylor & Francis Group    

年代:1971

数据来源: Taylor

摘要:

Recently [1] a complete hamiltonian, correct to orderc-2, was derived for a translating, rotating, vibrating, non-linear molecule. Here this work is extended to linear molecules; because of the unusual features of linear molecules particular attention is paid to the vibrational and rotational parts of the hamiltonian, and some simplification is reported. As for non-linear molecules a number of new terms appear in the hamiltonian: mass polarization corrections to the orbital Zeeman, spin-orbit and orbit-rotation interactions; spin-vibration, orbit-vibration and orbit-rotation interactions together with a vibrational Zeeman interaction. The final hamiltonian provides a starting point for future investigations of the possible effects of these novel interactions on the high resolution spectroscopy of open- and closed-shell linear molecules.

ISSN:0026-8976    

DOI:10.1080/00268977100100151

出版商:Taylor & Francis Group    

年代:1971

数据来源: Taylor

摘要:

Calculations have been made on the energies of the Rydberg states of H2O and H2S using a basis of wave functions of the united atoms (Ne or Ar). There is a large mixing of states induced by the potential of the protons, showing that the use of atomic quantum numbers (n, l, m) to designate the Rydberg bands is only a rough guide to their character.

ISSN:0026-8976    

DOI:10.1080/00268977100100161

出版商:Taylor & Francis Group    

年代:1971

数据来源: Taylor

摘要:

The transition probabilities and phase changes associated with passage through a potential curve crossing are derived in the form of connection formulae between WKB solutions on either side of the crossing point. The formulae are expressed in terms of three integralsvand ε±which may be evaluated for arbitrary potential curves and interaction function without knowledge of the associated wavefunctions. The theory, which is fully developed in the chemical energy region (< 100 ev), is applied to a model for the covalent-ionic crossing responsible for inelastic scattering of alkali atoms from neutral targets and its extension to the higher energy region for this model indicated.

ISSN:0026-8976    

DOI:10.1080/00268977100100171

出版商:Taylor & Francis Group    

年代:1971

数据来源: Taylor

ISSN:0026-8976    

DOI:10.1080/00268977100100181

出版商:Taylor & Francis Group    

年代:1971

数据来源: Taylor

ISSN:0026-8976    

DOI:10.1080/00268977100100191

出版商:Taylor & Francis Group    

年代:1971

数据来源: Taylor