Showing papers in "Chemical Physics Letters in 1988"

TL;DR: In this paper, an efficient algorithm for evaluating the second-order Moller-Plesset (MP2) energy directly from two-electron integrals in the atomic orbital basis, i.e., the integrals are not stored.

TL;DR: In this article, a new method for evaluating one-particle coupling coefficients in general configuration interaction calculation is presented, through repeated application and use of resolutions of the identity, two-, three-and four-body coupling coefficients and density matrices may be built in a simple and efficient way.

TL;DR: In this paper, a generalization of the Coupled-pair functional (CPF) is proposed to account for unlinked-cluster effects at the multireference level.

TL;DR: A spin correction procedure for removing the spin contamination from unrestricted Hartree-Fock and Moller-Plesset wavefunctions for singlet diradicals is examined in this article.

TL;DR: In this paper, rotational resonance occurs when the spinning speed is adjusted so that the condition ωδiso=nωr is satisfied, where ω is the difference isotropic chemical shifts, ωr is the spin speed and n is an integer.

TL;DR: A new implementation of the coupled cluster method including all single, double, triple and quadruple excitations (designated CCSDT) has been developed and carefully tested.

TL;DR: In this article, a field-cycling method is demonstrated whereby the nuclear spin order of para-enriched H2 is inserted adiabatically into a product molecule formed by molecular addition.

TL;DR: In this article, negative carbon clusters are reported in the size range from 2 through 29 atoms, with even-numbered chains having open shell electronic structures with high electron affinity, the odd chains having closed shell singlet ground states (for the neutral) and substantially lower electron affinity.

TL;DR: In this article, the theoretical principles of a new class of NMR experiments (DAS, dynamic angle spinning) which can remove not only the first-order broadening but also the second-order (or higher-order) broadenings are given.

TL;DR: In this paper, the authors reported the discovery of high-lying, very-long-lived Rydberg states in NO and determined the ionization potential of NO to be 74721.7 ± 0.4 cm−1.

TL;DR: The absorption, fluorescence and phosphorescence spectra of buckminsterfullerene are governed by a 1 T 1u ← 1 A g, 1 T 2g →1 A g and 3 T 2 g → 1 G transition, respectively.

TL;DR: The photodynamics of bacteriorhodopsin were studied by transient absorption and gain measurements after excitation with femtosecond pulses at 620 nm and 700 nm with a relaxation time of 200±70 fs as mentioned in this paper.

TL;DR: In this paper, a multi-reference Moller-Plesset perturbation theory (OVB MP2) is derived using an effective Hamiltonian formalism, characterized by the use of localized CAS SCF orbitals in order to achieve a quasi-degenerate (in terms of the one-electron reference Hamiltonian) reference space.

TL;DR: In this article, the relative phase and amplitude of two simultaneously applied lasers of frequency ω 1 and ω 3 = 3ω 1 was used to control product yields in photodissociation.

TL;DR: In this paper, the authors considered the transfer of population in a three-level system by near resonant stimulated Raman scattering, and showed that complete transfer is possible with cw lasers of moderate power provided a suitable spatial displacement of the pump and stimulating laser is introduced.

TL;DR: In this article, the authors derived analytical formulae for the energy gradient within the quadratic configuration interaction singles and doubles (QCISD) method and their implementation is discussed.

TL;DR: In this article, the interference of electrons passing through a benzene embedded in a polyacetylene chain is calculated using the electronic tunnelling probability coefficient and discussed with the help of the electronic differential density of states.

TL;DR: In this article, the basis set dependence of the exchange term in He 2, (LiH) 2 and Li + …H 2 O has been considerably reduced, matching exchange perturbation results and avoiding artificial attractive values appearing in other procedures of this kind.

TL;DR: In this paper, a new radial basis set is devised which is both (a) ideally suited to the log derivative boundary value problem, and (b) directly amenable to a discrete representation based on Gauss-Lobatto quadrature.

TL;DR: In this paper, the authors present the first application of infrared-visible sum-frequency generation to studies of liquid/solid interfaces, where the spectra in the CH stretch region of a saturated monolayer of octadecyltrichlorosilane (OTS) adsorbed at various interfaces bound by a fused silica substrate were measured and compared.

TL;DR: In this paper, a new rule for calculating chemisorption energies using the cluster model was proposed, based on the realization that relatively large clusters (50 atoms and more) often need to be prepared for bonding by making an excitation to a proper bonding state (such a state will always be easily accessible in an infinite cluster).

TL;DR: In this paper, it was shown that exposure of the LB films of cadmium arachidic acid to H 2 S gas results in an increase in thickness of about 3 A per layer.

TL;DR: In this article, a novel method for enhancing carbon spin diffusion in magic-angle spinning NMR experiments of solid samples is presented, which requires that the rotor frequency is adjusted to an integer fraction of the isotropic chemical shift difference between two particular carbon resonances.

TL;DR: In this article, the real-time dynamics of wave packet resonance (due to photofragment trapping) in the reaction of NaI is reported using femtosecond transition-state spectroscopy (FTS).

TL;DR: In this paper, the authors used photoionization efficiency measurements obtained for alkali clusters provided impetus for higher-resoln (33 nm) studies, and the new data cover the full range of cluster sizes: Nax, x <23 Methods of assigning ionization potentials are discussed.

TL;DR: The viscosity and temperature-controlled dynamical behavior of rhodamine dyes in the excited state has been investigated by stationary and time-resolved fluorescence measurements using synchrotron radiation.

TL;DR: In this paper, the quenching cross sections for most collision partners are found to be larger than classical collision cross sections; H atoms are mostly quenched faster than O atoms.

TL;DR: In this article, the resonanceenhanced multiphoton ionization spectra of uracil and thymine have been observed in the gas phase in a supersonic molecular beam.

TL;DR: In this paper, the authors consider the relationship between three variational principles which generate approximate time evolution in a parametrized manifold of wavefunctions and show that if the manifold can be parametrized by pairs of complementary parameters, the above principles are equivalent.

TL;DR: In this paper, a theory was presented to calculate the effective exchange integrals (J ab ) for exchange-coupled metal clusters on the basis of the spin-projected unrestricted Hartree-Fock (PUHF) molecular orbital method.