Some methods and applications of electron density distribution analysis

Accurate and efficient integration of the electron density function over arbitrary regions has been previously achieved by exploiting a separation of variables. Recently, a computer program has been written that calculates ρ, \documentclass{article}\pagestyle{empty}\begin{document}$ \buildrel{\rightharpoonup}\over{\nabla} $\end{document} ρ, and ∇ 2 ρ in an expeditious fashion, taking advantage of the separation of variables in the electron density function. Accurate integrations of ∇ 2 ρ over arbitrary regions can also be accomplished. The structure of the program is suited especially to vector processors. As a result of the efficiencies of these programs, functions of the electron density, such as the density itself, the surrounding electrostatic potential, ∇ρ, and ∇ 2 ρ have been calculated in three dimensions. Results of calculations for nitrated cubanes are presented illustrating how the effects of the nitro groups are manifested in the electron density and associated properties.