Probing low-frequency terahertz calculation: A comparison between periodic boundary conditions and cluster models

Abstract

Terahertz spectroscopy performs as a powerful tool for revealing valuable information on molecular interactions. In recent years, low-frequency terahertz simulation through periodic boundary conditions has proved to be a great success with regard to long-range force and complete noncovalent interaction rather than cluster models or unit cell models. However, quantum chemistry simulation with a limited number of molecules also enables many in-depth and comprehensive analytical methods, therefore, encouraging proving the outcome validity of the cluster models based on quantum chemistry calculation. In this article, we compared the computational results of both periodic boundary conditions and cluster models through solid-state density functional theory, revealing the necessity of a periodic structure in calculating low-frequency terahertz bands, which is instrumental for the selection of computational models for terahertz spectra.