Invited Review: Modern Methods for Accurately Simulating the Terahertz Spectra of Solids

Terahertz spectroscopy has proven to be a powerful tool for the study of condensed phase materials, opening research directions in a number of fields ranging from the pharmaceutical to semiconducting industries. Recent developments in terahertz technology have made this technique more accessible than ever before, and an increasing number of researchers are turning to terahertz spectroscopy for analysis and characterization of advanced materials. However, unlike mid-IR techniques, there do not exist any functional group specific transitions at terahertz frequencies, making the interpretation and assignment of terahertz spectral data more complex than complementary techniques. Through the aid of computational tools, incredible insights into the atomic-level dynamics occurring at terahertz frequencies have been uncovered, yet such highly accurate simulations require more care than traditional simulation methods in order to obtain such results. This review aims to highlight the recent advances in the computational assignment of terahertz spectral data, as well as showcasing common pitfalls to avoid, in order to demonstrate the utility of simulation methods for terahertz spectral assignment. Finally, cutting edge techniques and applications will be discussed, opening the door for future work in this exciting area of terahertz science.