This book describes different theoretical models developed to identify the near and mid infrared (IR) spectra of diatomic molecules isolated in the gas phase or subjected to environmental constraints, useful for the study of environmental sciences, planetology and astrophysics.

The applications presented show how molecular interactions modify the near and mid IR spectra of isolated diatomics under the effect of pressure, a nano-cage (substitution site, Clathrate, Fullerene, Zeolite) or surfaces, to identify the characteristics of the perturbing environment.

Pierre Richard Dahoo is Professor at the University of Versailles St Quentin (UVSQ), researcher at LATMOS, UMR 8190 CNRS, Manager of the University Institute of Technology of Mantes-en-Yvelines and Program Manager of the Chair "Materials Simulation and Engineering" of the UVSQ in Versailles, France.

Azzedine Lakhlifi is Lecturer at the University of Franche-Comté, and researcher at the UTINAM Institute, UMR 6213 CNRS, Observatory of Besançon, France.