In this Appendix we attempt to briefly review developments since the early 1990ies in the field of collision-induced absorption in gases. Many of the new contributions were announced, and numerous references to current literature were given in the proceedings of periodic conferences and special workshops. We mention especially the Proceedings of the biennial International Conferences on Spectral Line Shapes and the annual Symposia on Molecular Spectroscopy. New work in collision-induced absorption in gases has been reviewed in the Proceedings of a NATO Advanced Study Institute, a NATO Advanced Research Workshops, and in a recent monograph Molecular Complexes in Earth's, Planetary, Cometary, and Interstellar Atmospheres. A multi-authored volume, a significantly augmented treatment of bremsstrahlung, is also of interest here, for example when electrically charged particles exist in dense, largely neutral and hot environments, e.g., in shock waves, in the atmospheres of “cool” white dwarf stars, in sonoluminescence studies, etc.

Binary Interaction-Induced Dipoles.Ab initio quantum chemical calculations of interaction-induced dipole surfaces are known for some time (Section 4.4, pp. 159 ff.) Such calculations were recently extended for the H2—He and H2—H2 systems, to account more closely for the dependencies of such data on the rotovibrational states of the H2 molecules.