Nanophotonics and spectroscopy has advanced rapidly in recent years. Experimental research on nanophotonics is very active. In addition to experimental research on the principles and applications of nanophotonics, computational simulation research on its various physical mechanisms and phenomena is equally important. The simulation of the optical properties of molecules or crystals, such as electronic spectra (absorption and emission spectra, etc.) and vibrational spectroscopy has extraordinary guiding significance for experiments. The current computational simulation technology can also explain and analyze the physical mechanisms behind phenomena. However, among the many computational simulation software programs available, the operation methods and application scenarios are different. The barrier for new users to conduct research with computational simulation is high. Even for researchers with some experience, it is not easy to develop a comprehensive understanding of the various software programs, keywords, programming languages and auxiliary programs. This book serves as an introductory book for beginners to get started with the technology, and a handbook for experienced readers to quickly look up for commands and script usage. It is a handy reference for graduate students and researchers engaged in the study of photonics and optics.

Mengtao Sun obtained his Ph.D. in 2003 from the State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences (CAS). From 2003 to 2006, he worked as a postdoc at the Department of Chemical Physics, Lund University. Since 2006, as an Associate Professor, he has worked at the Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, CAS. In 2016, he became a Full Professor in University of Science and Technology Beijing, China. His current research interests focus on one and two photon absorptions in organic molecules, two dimensional (2D) materials and plasmonics, as well as the exciton-plasmon coupling interaction for molecular spectroscopy and surface catalytic reaction.Xijiao Mu, Ph D graduated from University of Science and Technology Beijing in 2022. He is principal investigator in State Key Laboratory of Applied Organic Chemistry, Key Laboratory of Nonferrous Metal Chemistry and Resources Utilization of Gansu ProvinceCollege of Chemistry and Chemical Engineering, Lanzhou University.

Chapter 1 Introduction.- Chapter 2 Theoretical basis of computational simulation.- Chapter 3 Calculation and analysis of electron transition spectra.- Chapter 4 Vibration spectrum calculation and analysis.- Chapter 5 Calculation of nonlinear optical properties.- Chapter 6 Calculation and analysis of molecular chiral spectra.- Chapter 7 First principles calculation of optical properties of solids.- Chapter 8. Application of electronic structure methods in optical calculation and analysis.