Simulation packages Polar

The density functional calculations were performed using the Vienna Ab Initio Simulation Package (VASP). ° The spin-polarized generalized gradient approximation, Perdue—Wang exchange correlation function, and ultrasoft pseudopotentials were used. ... 

A. Laaksonen, Computer Simulation Package for Liquids and Solids with Polar Interactions I McMOLDYN/H20 Aqueous Systems, Comp. Phys. Comm., 42 (1986), 271. 

Ethanol and aqueous ethanol mixtures play important roles as food simulants for the determination of migration of substances from packaging into foods. Depending on the polarity of the plastic one can use pure ethanol (for nonpolar plastics) or aqueous ethanol mixtures up to 50/50 % (for polar plastics) as alternative simulants to edible oils (see Chapters 9,10 and 11). The estimation of partition coefficients in poly-mer/simulant systems is consequently of practical importance. It is possible to do this for polyolefins in contact with alcohol and aqueous alcohol mixtures with the help of an equation analogous to Eq. (4-100) (Piringer, 1993) ... 

This combination of Equations [5] and [16] is called the Generalized Born/Surface Area model (GB/SA), and it is currently available in the Macro-ModeP computer package. The speed of the molecular mechanics calculations is not significantly decreased by comparison to the gas phase situation, making this model well suited to large systems. Moreover, the model takes account of some first-hydration-shell effects through the positive surface tension as well as the volume polarization effects. A selection of data for aqueous solution is provided later (Table 2), and the model is compared to experiment and to other models. Nonaqueous solvents have been simulated by changing the dielectric constant in the appropriate equations, 8 but to take the surface tension to be independent of solvent does not seem well justified. 

Impulse Noise Analysis Results. ANITA-lite measured about 130,000 distinct events, with an approximate rate of 5 events per minute. Fig. 6 shows examples of the major classes of impulsive noise encountered. The vast majority of triggered events are due to local payload interference such as switching noise from the Support Instrument Package. The duration of this class of events exceeds several hundred nanoseconds and a few events exhibit circular polarization for a portion of the pulse. The bottom two panes show an example of a synthetic pulse injected into the data stream to simulate a true signal event. The pulse is coherent and aligned across all channels. Preliminary studies of event selection procedures were conducted. They yield no passing events, while 97% of simulated Askaryan-induced impulses with amplitude 5<7 above noise survive (Miocinovic et al., 2004). 

For condensed-phase and macromolecular simulations, we have written an X-Pol software package using the C-p-p language, which has been incorporated into NAMD and CHARMM. The X-Pol program can be used with the popular NDDO-based semiempirical Hamiltonians as well as the recently developed polarized molecular orbital (PMO) model. - Molecular d3mamics simulations of liquid water have been carried out using the NAMD/X-Pol interface. In addition, we have used an earlier version of the X-Pol model in Monte Carlo simulations of liquid water. 

Our dynamical simulation with SET is implemented into the GAMESS package. [357] The basis functions used were those of the TZV basis set [120], to which an s-type diffusion base and two sets of p-type polarization functions were added on hydrogen atoms while s- and p-type diffusion functions were augmented on oxygen atoms. (The exponent is 0.03600 for the s-type diffusion base, 0.08450 for the s- and p-type diffusion bases. 

The knowledge of the evolution with time of the molecular dipole moments is mandatory for the calculation of IR spectra with MD simulations. In the modem theory of polarization, the dipole moment of the (periodic) box cell is calculated with the Berry phase representation, as implemented in the CPMD and CP2K packages [98]. Briefly, in the limit where the F point approximation applies, the electronic contribution to the cell dipole moment (where a = x,y, z) is given by [99]... 

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