¹⁴N NQR Study of Urea and Thiourea

Abstract

Nuclear quadrupole resonance (NQR) is a newly developed branch of radio frequency (RF) spectroscopic technique, allowing the detection of many substances containing quadrupole nuclei, such as14N and35Cl, widely existing in explosives and narcotics respectively. In this paper, we focus on the research of its detection mechanism for14N in urea and thiourea. Based on the Density Functional Theory (DFT), employing Beckes three-parameter hybrid functional combined with Lee-Yang-Parr correlation functional (B3LYP), with 6-311++G(d,p) basis set, we have obtained the quantum chemical calculations by using Gaussian 09. Furthermore, experimental results and some discussions related are also presented. At last, we find that the absolute values of relative errors of NQR frequencies are all less than 2%, which indicates that this study is reasonable.