The computed electrostatic potentials on C,H,N,O molecular solids and nitrogen-rich C,H,N,O salts are used in analyzing and comparing intralattice attractive forces and crystal densities in these two categories of compounds. Nitrogen-rich C,H,N,O salts are not an assured path to high densities. To increase the likelihood of high densities, small cations and large anions are suggested. Caution i...

In this lecture a new formalism for constructing electromagnetic surface sources for static axisymmetric electrovacs is presented. The electrostatic and magnetostatic sources are derived from the discontinuities of the scalar potentials. This formalism allows the inclusion of two kinds of dipole sources: Sheets of dipoles and the dipole moment of a distribution of monopoles. It is a generalizat...

Different schemes for the treatment of long-ranged electrostatic interactions will be examined for water simulations using the polarizable fluctuating charge potential. Several different methods are compared, including Ewald sums, potential shifting, spherical truncation and reaction field corrections. For liquid water, properties such as the energy, pressure, dynamics and structure are more se...

mental process by which virtually all organisms obtain energy. For this reason, biochemists are interested in electrochemically characterizing proteins that make up electron transport pathways. They are also interested in understanding at a molecular level how a protein’s structure influences its electron transfer function. In this study, the electron transfer protein rubredoxin (F1) from the d...

Scanning transmission electron microscopy (STEM) is the most widespread adopted tool for atomic scale characterization of two-dimensional (2D) materials. Many 2D materials remain susceptible to beam damage, despite standardized practice reduce energy from 200 keV 80 or 60 keV. Although, all elements present can be detected by electrostatic potential imaging using integrated differential phase c...

Four methods for deriving partial atomic charges from the Ž quantum chemical electrostatic potential CHELP, CHELPG, Merz-Kollman, and . RESP have been compared and critically evaluated. It is shown the charges strongly depend on how and where the potential points are selected. Two alternative methods are suggested to avoid the arbitrariness in the point-selection schemes and van der Waals exclu...

All electrostatic fields E (i.e., ones with no time dependence) can be derived from a scalar potential V (E = −∇V ) and hence obey ∇ × E = 0. The latter condition is sometimes considered to be a requirement for electrostatic fields. Show, however, that there can exist time-dependent electric fields for which ∇ × E = 0, which have been given the name “electrostatic waves”. In particular, show th...

PHEPS (pH-dependent Protein Electrostatics Server) is a web service for fast prediction and experiment planning support, as well as for correlation and analysis of experimentally obtained results, reflecting charge-dependent phenomena in globular proteins. Its implementation is based on long-term experience (PHEI package) and the need to explain measured physicochemical characteristics at the l...

Amino acids display significant variation in propensity for the alpha R-helical, beta-sheet, and other main chain conformational states in proteins and peptides. The physical reason for these preferences remains controversial. Conformational entropy, steric factors, and the hydrophobic effect have all been advanced as the dominant underlying cause. In this work, we explore the role of a fourth ...

A method is presented for the efficient evaluation of long-range electrostatic forces in combined quantum mechanical and molecular mechanical (QM/MM) calculations of periodic systems. The QM/MM-Ewald method is a linear-scaling electrostatic method that utilizes the particle mesh Ewald algorithm for calculation of point charge interactions of molecular mechanical atoms and a real-space multipola...