摘要:

Bound to free emission centred near 420nm is reported from heavily predissociated levels of H2O/D2O[Ctilde](1B1)000(τ < 6ps) to the dissociativeÃ1B1state. The quantum yield for fluorescence is small (∼ 10-4) and provides an estimate for the radiative lifetime of the D2O ([Ctilde]→Ã) emission. The ([Ctilde]→Ã) fluorescence excitation spectrum has been modelled to obtain refined heterogenous predissociation rates for D2O ([Ctilde]1B1→[Btilde]1A1) transfer. This has allowed the OD(A2Σ+) photofragment fluorescence excitation spectrum to be modelled to obtain theJ′adependent Renner-Teller crossing probability for[Btilde]1A1→Ã1B1transfer during dissociation, over a wide range ofa-axis rotation. The results are in good, qualitative agreement with theory and provide insight into the dynamics of dissociation on the[Btilde]1A1surface. Resolved photofragment fluorescence excitation spectra for selected rotational levelsN′, in OD (A2Σ+)v′ = 0 show a correlation betweenN′ and the[Btilde]→Ãcrossing probabilities. This provides experimental evidence for the correlation between ‘direct’ trajectories and high product rotation and between ‘indirect’, bending trajectories and low product rotation, as suggested by previous 3-D scattering calculations. The effect of this correlation and of the intersections of[Btilde]1A1withÃ1B1and[Xtilde]1A1, on the[Btilde]state dynamics and on the OD (A2Σ+) quantum yield, rotational distributions and alignments are discussed.

ISSN:0026-8976    

DOI:10.1080/00268978600100101

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

The three-dimensional HNC equation for a truncated Lennard-Jones potential is numerically solved. We have found that the direct correlation function asymptotically behaves asr-2exp (-2r/ξ), ξ being the correlation length. The contribution coming from this behaviour has been incorporated into the computation of the isothermal compressibility κT. The results seem to indicate that the HNC equation does not have real solutions inside a certain region in the temperature-density plane, whose boundary line has been fitted to power laws. When approaching this boundary, κTand ξ tend to finite values. So, a true critical point, where κTand ξ would diverge, is not present.

ISSN:0026-8976    

DOI:10.1080/00268978600100111

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

Calculations on the KVV Auger spectra of the CO molecule are carried out in the framework of the discrete variationalXα= method (DVM-Xα) with accounting for the singlet-triplet splittings of the Auger energies. The relative reliability of various calculations approaches which are in current use is estimated, based on the comparison of corresponding results of calculations with each other, and with the experimental data for the KVV Auger spectra of the CO molecule as a test example. It is shown that the level of accuracy of the DV-Xαmethod approaches that ofab initiocalculations with the inclusion of configuration interactions (CI) for delocalized electronic states and is somewhat worse for the strongly localized ones.

ISSN:0026-8976    

DOI:10.1080/00268978600100121

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

It is often desirable to determine the parameters of an analytical representation of a molecular potential energy surface by a least squares fit of the vibrational energy levels to experimental values. The variational method is the only accurate method to obtain these levels, and this paper describes our most efficient procedure for the construction of the hamiltonian matrix. Applications of the procedure to CO2and SO2are described. Advances made in reducing the size of the variational problem are also discussed.

ISSN:0026-8976    

DOI:10.1080/00268978600100131

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

The canonical ensemble molecular dynamics method proposed by Nosé (1984,Molec. Phys.,52,255 and 1984,J. chem. Phys.,81,511) is extended to include more than one temperature control variable. This extension makes it possible to control temperatures of different degrees of freedom (e.g. translation and molecular rotation) separately.

ISSN:0026-8976    

DOI:10.1080/00268978600100141

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

Time-reversal symmetry is exploited to halve the computational effort for the calculation of nuclear spin-spin coupling constants in the framework of the relativistic analogue of Ramsey's theory. The derivation is given for quaternionic relativistically parameterized extended Hückel (QATREX) wavefunctions, but the arguments used apply to any quantum-chemical method which generates Kramers pairs. Applications to selected heavy-element fluoridesMFn(n= 2, 4, 6) are given based on charge-iterated REX calculations.

ISSN:0026-8976    

DOI:10.1080/00268978600100151

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

The electrostatic theory of magnetic relaxation of quadrupolar nuclei in electrolyte solutions is reinvestigated. Contrary to previous treatments purely microscopic expressions for the field gradient correlation function are derived. The influence of solvent dipoles and quadrupoles as well as the influence of other ions in the solution are considered. Due to the collective character of the correlation functions static and dynamic cancellation of two-particle by three-particle contributions is expected. In all cases the resulting correlation functions closely resemble those of interaction-induced spectra. Some general properties of these interaction-induced field gradient correlation functions are discussed, which differ considerably from those of previous investigations.

ISSN:0026-8976    

DOI:10.1080/00268978600100161

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

Using velocity modulation detection, infrared diode laser absorption spectra of seventeen transitions of the fundamental band of HCl+have been measured covering both2Π1/2and2Π3/2states of H35Cl+and H37Cl+. The transitions were assigned on the basis of their absolute positions and Λ doublet splittings predicted by earlier optical spectra. Some of the additional lines detected, but not yet accurately measured, are tentatively assigned to hot band transitions in HCl+.

ISSN:0026-8976    

DOI:10.1080/00268978600100171

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor