quasicrystals are a group of materials with the quasi-periodic structure, and since their discovery in 1980 their specially interesting physical properties have attracted the attention of many researchers. the lack of translational periodicity makes the numerical calculations of their physical properties much more difficult than the crystalline solids. in this work we present a detailed numeric...

Vibrational relaxation is an important physical process in hypersonic flows. Activation of the vibrational mode affects the fundamental thermodynamic properties and finite rate relaxation can reduce the degree of dissociation of a gas. Low fidelity models of vibrational activation employ a relaxation time to capture the process at a macroscopic level. High fidelity, state-resolved models have b...

In memoriam Professor Dr. Werner Zeil The microwave spectrum of tricarbon oxide sulphide (3-thioxo-l,2-propadiene-l-one), 0 = C = C = C = S , has been measured in the frequency range from 8 to 40 GHz and includes vibrational satellite lines arising from the vibrational manifold of the lowest-lying doubly-degenerate bending mode i>7. The method of analysis followed the theory of rotation-vibrati...

Modern ab initio and multiscale methods enable the simulation of vibrational properties of very large molecules. Within the harmonic approximation, the traditional generation of the spectra based on the force field diagonalization can become inefficient due to the excessive demands on computer time and memory. The present study proposes to avoid completely the matrix diagonalization with a dire...

in recent years there has been considerable interest in the structures, energies and thermodynamics of(gan)4 clusters and it is the subject of many experimental and theoretical studies because of theirfundamental importance in chemical and physical process. all calculation of this study is carried outby gaussian 98. geometry optimization for (gan)4 nanocluster are be fulfilled at b3lyp, b1lypan...

Computations are presented to describe and analyze the high levels of infrared laser induced vibrational excitation of a monolayer of absorbed (13)CO on a NaCl(100) surface. Extending the vibrational site-to-site surface hopping technique of Corcelli and Tully, kinetic Monte Carlo computations are used to incorporate single-quantum vibrational pooling and depooling of the (13)CO by phonon excit...

A global, analytical potential energy surface for the ground electronic state of HOBr has been determined using highly correlated multireference configuration interaction wave functions and explicit basis set extrapolations of large correlation consistent basis sets. The ab initio data have been fit to an analytical functional form that accurately includes both the HOBr and HBrO minima, as well...