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In this paper we discuss the performance of the non-iterative state-specific multireference coupled cluster (SS-MRCC) methods accounting for the effect of triply excited cluster amplitudes. The corrections to the Brillouin-Wigner and Mukherjee's MRCC models based on the manifold of singly and doubly excited cluster amplitudes (BW-MRCCSD and Mk-MRCCSD, respectively) are tested and compared with exact full configuration interaction results for small systems (H2O, N2, and Be3). For the larger systems (naphthyne isomers) the BW-MRCC and Mk-MRCC methods with iterative singles, doubles, and non-iterative triples (BW-MRCCSD(T) and Mk-MRCCSD(T)) are compared against the results obtained with single reference coupled cluster methods. We also report on the parallel performance of the non-iterative implementations based on the use of processor groups. [ABSTRACT FROM AUTHOR]

Using quantum-hydrodynamic model, the phenomenon of the stimulated Brillouin scattering of a laser radiation in an unmagnetized piezoelectric semiconductor has been examined in detail. It is noticed that the Bohm potential in the electron dynamics of the semiconductor plasma enhances drastically the growth rate of the stimulated Brillouin scattering at higher values of the electron number density of the semiconductor plasma and the wave number of the electron-acoustic wave in the semiconductor. [ABSTRACT FROM AUTHOR]

Motivated by recent long scale-length single- and multiple-beam experiments conducted on LLE’s OMEGA laser system [W. Seka et al., Phys. Rev. Lett. 89, 175002 (2002)], we have simulated backward stimulated Brillouin scattering (SBS) in inhomogeneous direct drive plasmas where a critical surface is present at all times. This was achieved by adapting pF3D, a parallel, three-dimensional laser–plasma interaction code developed at the Lawrence Livermore National Laboratory [R. L. Berger et al., Phys. Plasmas 5, 4337 (1998)]. The shortcomings of the paraxial approximation, inherent in pF3D, were identified and circumvented via a practical approach that has led to an improved understanding of the experiments. The results show a qualitative agreement between the simulated and experimental SBS backscattered power reflectivity, with the conclusion that the time dependence of the SBS reflectivity is governed by target hydrodynamics and a quantitative agreement in the blue-shift in the frequency of reflected light. The simulations have also shown a sensitivity of the backscattered reflectivity to the amplitude of the specularly reflected signal of an “opposing” beam. © 2004 American Institute of Physics. [ABSTRACT FROM AUTHOR]