Showing papers in "Chemical Physics Letters in 1990"

TL;DR: In this article, a multi-configurational approach to the time-dependent Schrodinger equation is proposed, which can be used for n degrees of freedom and for any choice of the number of configurations.

TL;DR: In this article, a direct method for evaluating the gradient of the second-order Moller-Plesset (MP2) energy without storing any quartic quantities, such as two-electron repulsion integrals (ERIs), double substitution amplitudes or the two-particle density matrix, was presented.

TL;DR: In this paper, the authors formulate semi-direct MP2 methods that utilize disk space (which is usually much larger than memory size) for the steps that require most storage, and show that these methods are superior to conventional algorithms despite requiring less disk space.

TL;DR: In this paper, a non-iterative method is presented to evaluate the full set of fifth-order corrections to CCSD and QCISD and assess their accuracy compared to full CI for the very sensitive Be 2 curve and other cases.

TL;DR: In carbon smoke samples prepared from vaporized graphite at elevated quenching gas pressures (e.g. > 100 Torr He) new absorption features have been observed in the infrared (the strongest at 1429, 1183, 577, and 528 cm −1 ).

TL;DR: In this article, a hybrid approach based on the LCGTO-MCP-LSD method was proposed to solve the Kohn-Sham equations with quasi-Newton algorithms.

TL;DR: In this article, the first efficient detection of individual fluorescent molecules in solution was reported, which constitutes a significant advance in ultrasensitive detection that should have a variety of applications in biological and chemical science.

TL;DR: In this article, the complex permittivity spectra of the hydrogen-bonding liquids water, methanol, ethanol, 1-propanol, and 2-Propanol have been determined in the frequency range 0.95-89 GHz.

TL;DR: In this paper, a method for sensitization of highly porous TiO2 electrodes by in situ prepared quantum size CdS particles (40-200 A) was presented, achieving a photocurrent efficiency of more than 70% and a photovoltage of 400 mV.

TL;DR: In this paper, the authors reported that one direct CI iteration takes about 1.2-1.4 min per million determinants on an IBM 3090/VF and that the CPU time varies linearly with the dimension of the matrix from one million to more than one billion.

TL;DR: In this article, a radio-frequency pulse envelopes are presented for selective inversion and in-phase excitation in NMR, which consist of superpositions of three or four time-shifted Gaussians with optimized widths and peak amplitudes.

TL;DR: In this article, a technique to produce samples consisting primarily of C60 and C70 by fractional sublimation of carbon soot was found and used to produce solid films of these molecules.

TL;DR: In this paper, a method for measuring nuclear magnetic dipole couplings in NMR spectra of solids undergoing rapid magic angle spinning (MAS) is described. But the method is not suitable for non-crystalline solids.

TL;DR: In this paper, temperature-dependent accumulated photon echo, fluorescence lifetime and fluorescence quantum yield measurements were reported on aggregates of the dye pseudoisocyanine bromide in an ethylene glycol/water glass.

TL;DR: In this paper, a new method for calculating classical trajectories on molecular ab initio potential energy surfaces is presented, where equations of motion are integrated on a sequence of model surfaces constructed from analytically calculated molecular gradients and Hessians.

TL;DR: In this paper, a linear exciton-phononon scattering model was proposed to explain the temperature-dependent homogeneous width and shift of the J-band of pseudoisocyanine bromide.

TL;DR: In this paper, the surface potential of monolayers of alkyl thiols adsorbed on gold have been measured using the Kelvin technique and the potential has been found to vary linearly with increasing chain length, n, for 6⩽ n ⩽22.

TL;DR: In this paper, transient alkyl radicals and triplet-state molecules are generated simultaneously in solution by laser flash irradiation, and chemically induced electron polarization (CIDEP) of the radicals is studied by time-resolved ESR spectroscopy.

TL;DR: In this article, the authors show how ab initio quantum chemistry methods recently developed for calculating anharmonic constants about a potential minimum can be readily adapted to obtain those related to a transition state, thus providing a rigorous and practical way to apply this non-separable transition state theory.

TL;DR: The mass spectra of larger clusters are well explained by the completion of icosahedral or cuboctahedral shells of atoms as discussed by the authors, while small clusters (n, n ⩽ 1500) appear to be due to the filling of electronic shells.

TL;DR: In this paper, the best results were obtained with Si 3 N 4 sputtered on oxidized silicium wafers, both n-type and p-type majority carriers are effective depending upon the ambient atmosphere.

TL;DR: In this article, the cross-correlation between dipole and shift anisotropy relaxation mechanisms for the 15 N nucleus of the peptide bond was analyzed using the human epidermal growth factor (hEGF).

TL;DR: In this article, a simple and powerful approach to constructing discrete variable representations for the solution of quantum mechanical problems by focusing on properties of the underlying basis set is presented. But this approach is restricted to spherical polar coordinates with azimuthal symmetry.

TL;DR: In this article, the geometrical sequence formula to generate orbital exponents of GTO basis sets is compared with other two generating formulas termed as well-tempered, for atoms from He to Cd.

TL;DR: Second-harmonic generation from powders of a series of three aromatic intramolecular charge transfer moieties of D 3h symmetry is reported in this paper, where one compound is shown to be active while its symmetric structure precludes any molecular non-linear contribution of a vectorial nature such as usually prevails in polar paranitroaniline-like systems.

TL;DR: In this paper, a close coupling calculation of integral cross sections for the reaction F+H 2 (v = 0, j = 0)→FH( v ′ j ′)+H has been performed in the threshold energy range using hyperspherical coordinates.

TL;DR: In this paper, an absolute 31 P shielding scale based on the PH 3 molecular beam data is established and the absolute shielding of the standard liquid reference (85% aqueous H 3 PO 4 ) is found to be 328.35 ppm, based on PH 3 being 594.45 ± 0.63 ppm.

TL;DR: In this paper, the authors reported the use of large supercomputer resources to perform the first ab initio calculations on the polarisability and magnetisability of C 60 and its smaller analogue C 20 2+.

TL;DR: In this article, the Fourier transform four-wave mixing (FT 4WM) formalism is applied to femtosecond optical-heterodyne detected optical Kerr effect data for pyridine liquid.

TL;DR: In this paper, the C 6v symmetry structure of Na + -benzene and the small charge transfer from benzene to Na + suggest that the bonding of the ion complex is largely electrostatic in nature.