Theoretical study of surface-enhanced Raman spectroscopy of dimethyl methylphosphonate

Abstract

In this study, the surface-enhanced Raman spectroscopy spectra of dimethyl methyl phosphonate, which serves as a surrogate for the chemical warfare agent sarin, were modeled using density functional theory calculations. In addition, the fundamental mechanisms underlying the enhancement of surface-enhanced Raman spectroscopy are investigated. A comprehensive examination was conducted of the adsorption behavior and Surface-Enhanced Raman Spectroscopy enhancement effects resulting from the interaction between dimethyl methylphosphonate and silver clusters. Moreover, a comparison was made between the findings of the present study and the results of previous experiments in order to ascertain the optimal positions for the adsorption of silver clusters on dimethyl methylphosphonate molecules. In this article, the kinetics of the interaction between dimethyl methylphosphonate and silver clusters were theoretically explored through six different adsorption configurations. It was found that the configuration involving the dimethyl methylphosphonate structure and silver clusters containing three silver atoms exhibited the highest stability. By integrating Raman spectroscopic data with our theoretical insights, the vibrational modes, Raman spectra, and surface-enhanced Raman spectra of dimethyl methylphosphonate molecules were systematically correlated using Gaussian 09 and GaussView 5.0.8 software for detailed image-based analysis.