Semiclassical simulations in materials science
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abstract
Semiclassical simulations in materials science originated with the work of Sankey, Menon, and Allen in 1985, and of Car and Parrinello that same year. Here we briefly review some recent studies by the present authors using our method of semiclassical electron-radiation-ion dynamics (SERID). In particular, Zhou et al. and Jiang et al., respectively, determined the optimal duration and optimal timing for a series of femtosecond-scale laser pulses to excite a specific vibrational mode in a general chemical system. A set of such modes (or even a single characteristic mode) can be used as a "fingerprint" for characterizing a particular molecule or a complex in a solid. One can therefore envision many applications, ranging from fundamental studies to detection of chemical or biological agents. Lin et al. found that excited electrons automatically equilibrate to a Fermi-Dirac distribution within roughly 100fs, solely because of their coupling to the nuclear motion, even though the resulting electronic temperature is one to two orders of magnitude higher than the kinetic temperature defined by the nuclear motion. Microscopic simulations like these can then provide the separate electronic and kinetic temperatures, chemical potentials, pressures, and nonhydrostatic stresses required as input for studies on larger length and time scales. 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
