Nuclear Quadrupole Interactions in Nuclear Quadrupole Resonance Detection of Energetic and Controlled Materials: Theoretical Study

Abstract

There has been a growing interest in nuclear quadrupole resonance (NQR) techniques useful for the detection of explosives and drugs in solid state systems. This paper uses the first-principles one-electron Hartree–Fock theoretical method to study the nuclear quadrupole interaction parameters e2qQ and η for the 14N nuclei in the explosives RDX and β-HMX as well as the drugs cocaine and heroin. It has been found in our earlier published investigations reviewed here that there is very good agreement for our calculated e2qQ and η for 14N, for all these four systems, and experiment. We also present our unpublished theoretical results for cocaine with an HCl molecule attached. We successfully explain quantitatively the drastic decrease in e2qQ in going to cocaine-HCl from cocaine-free base as well as the observed substantial increase in η and discuss the implications of these dramatic changes for NQR detection in general.