Procedure for correcting variational R-matrix calculations for polarization response

Using standard bound-state methodology, variational calculations of molecular R matrices can severely underestimate polarization response in the near-target region inside the R-matrix boundary. An ''⌬R'' procedure is proposed here as an easily implemented but significant improvement of such R matrices. The efficacy of this procedure is demonstrated in calculations of differential and integral cross sections for vibrationally elastic e-C

Semirelativistic DWBA for the Ionization of Closed Shell Atoms at Intermediate Energies

We develop a semirelativistic distorted-wave Born approximation applicable to the study of (e,2e) processes at intermediate energy. Using this method, we investigate the influence of relativistic interactions for the continuum and bound electrons on the parameters describing spin-polarized (e,2e) experiments on xenon at intermediate energy (E0 = 150 eV) and for asymmetric kinematics

DENSITY-FUNCTIONAL MOLECULAR DYNAMICS SIMULATIONS OF SHOCKED MOLECULAR LIQUIDS

Molecular dynamics (MD) simulations have been performed for highly compressed fluid deuterium, nitrogen, and oxygen, in the density and temperature regime of shock-compression experiments, using density functional (DF) electronic structure techniques to describe the interatomic forces. The Hugoniots derived from the calculated equation-of-state for deuterium does not exhibit the large compression predicted by the recently reported laser-driven experiments. However, the Hugoniot derived for nitrogen and oxygen agree well with explosively-driven and gas-gun experiments. The nature of the fluid along the Hugoniot, as calculated with DF-MD, has been analyzed. All three species (D2, N2, amd 02) undergo a continuous transition from a molecular to a partially dissociated fluid containing a mixture of atoms and molecules

Dynamic X-ray diffraction observation of shocked solid iron up to 170 GPa

Investigation of the iron phase diagram under high pressure and temperature is crucial for the determination of the composition of the cores of rocky planets and for better understanding the generation of planetary magnetic fields. Here we present X-ray diffraction results from laser-driven shock-compressed single-crystal and polycrystalline iron, indicating the presence of solid hexagonal close-packed iron up to pressure of at least 170 GPa along the principal Hugoniot, corresponding to a temperature of 4,150 K. This is confirmed by the agreement between the pressure obtained from the measurement of the iron volume in the sample and the inferred shock strength from velocimetry deductions. Results presented in this study are of the first importance regarding pure Fe phase diagram probed under dynamic compression and can be applied to study conditions that are relevant to Earth and super-Earth cores