A GLOBAL POTENTIAL ENERGY SURFACE FOR HNO$_3$

Abstract

A potential energy surface has been fit to the energy and energy gradient for thousands of configurations of HNO$_3$. Prior to explicit inclusion of data for the cis,perp-HOONO conformation, this isomer was predicted to be a local minimum on the fitted surface. The status of cis,perp-HOONO as a minimum was later confirmed through {\it ab initio} frequency calculations. Molecular dynamics simulations were carried out on the fitted surface to investigate the cis/trans isomerization of the HOONO structure.