Ab initio perturbed ion calculations were performed for the cubic, orthorhombic, hexagonal, and monoclinic phases of PbF2. A complete characterization of these phases was achieved in terms of the potential energy surfaces, the equations of state, and the phase-transition pressures. Thermal effects were included via a quasiharmonic nonempirical Debye model. The internal parameters of the unit ce...

We propose a procedure to determine the effective nuclear shell-model Hamiltonian in a truncated space from a self-consistent mean-field model, e.g., the Skyrme model. The parameters of pairing plus quadrupole-quadrupole interaction with monopole force are obtained so that the potential energy surface of the Skyrme HartreeFock + BCS calculation is reproduced. We test our method for N = Z nuclei...

Tight-binding molecular dynamics simulations of the adsorption of O2/Pt(111) have been performed based on an ab initio potential energy surface. We demonstrate that, contrary to common belief, in this system the whole adsorption probability as a function of the kinetic energy can be understood in terms of trapping into chemisorbed molecular precursor states. This provides a novel unified pictur...

We have used a discrete variable representation (DVR) with absorbing boundary conditions (ABC) to calculate initial state-selected reaction probabilities and photodetachment intensities. We apply this method to the OH + H, reaction constrained to a plane with the OH bond frozen. The calculated reaction probabihties have al1 the qualitative features observed in full dimensional calculations. We ...

A space warping method, facilitating the modeling of large-scale conformational changes in mesoscopic systems, is presented. The method uses a set of "global (or collective) coordinates" that capture overall behavior, in conjunction with the set of atomic coordinates. Application of the space warping method to energy minimization is discussed. Several simulations where the method is used to det...

High-resolution spectroscopy measures the transitions between energy levels with high accuracy; typically, uncertainties are in the region of 1 part in 108. Although it is possible, under favorable circumstances, to obtain this sort of accuracy by fitting effective Hamiltonians to observed spectra (see Bauder 2011: Fundamentals of Rotational Spectroscopy, this handbook), such ultrahigh accuracy...

A modified ab initio potential energy surface ~PES! is used for calculations of ozone recombination and isotopic exchange rate constants. The calculated low-pressure isotopic effects on the ozone formation reaction are consistent with the experimental results and with the theoretical results obtained earlier @J. Chem. Phys. 116, 137 ~2002!#. They are thereby relatively insensitive to the proper...

were clinically normal. In a subset of 16 subjects, variability in serial maps was assessed as the root-meansquare difference in time-integral values between maps using the same electrode application (recordings separated by 15 minutes) as well as when different electrode applications were required (recordings separated by 1-7 days). Isointegral maps of the QRS, ST-T, QRST, ST-segment and Q-zon...