The papers collected in this volume were presented at an international symposium on Computational Methods in Chemistry. This symposium was sponsored by IBM Germany and was held September 17-19, 1979, in Bad Neuenahr, West Germany. According to Graham Richards [Nature 278, 507 (1979)] the "Third Age of Quantum Chemistry" has started-;-where the results of quantum chemical calculations have become so accurate and reliable that they can guide the experimentalists in their search for the unknown. The particular example highlighted by Richards was the suc cessful prediction and subsequent identification of the relative energies, transition probabilities and geometries of the lowest triplet states of acetylene. The theoretical predictions were based chiefly upon the work of three groups: Kammer [Chern. Phys. Lett. ~, 529 (1970)] had made qualitatively correct predictions; Demoulin [Chern. Phys. 11, 329 (1975)] had calculated the potential energy curves for the two lowest triplet states (3 and 3 ) of B A acetylene; and Wetmore and Schaefer III [J. Chern. Phys. ~~ 1648 (1978)] had determined the geometries of the cis (3B and ~A ) and the trans (3B and 3A ) isomers of these two sta~es. Inua 2 2 guided search, Wendt, Hunziker and Hippler [J. Chern. PHys. 70, 4044 (1979)] succeeded in finding the predicted near infrared absorption of the cis triplet acetylene (no corresponding absorp tion for the trans form was found, which is in agreement with theory), and the resolved structure of the spectrum confirmed the predicted geometries conclusively.

Inhalt
Setting up, Using, and Maintaining Computer-Readable Spectra Compilations.- The Solution to the General Problem of Spectral Analysis Illustrated with Examples from NMR.- Determination of the Structures of Organic Molecules by Computer Evaluation and Simulation of Infrared and Raman Spectra.- Phenomena in Photoelectron Spectroscopy and Their Theoretical Calculation.- Novel Radical Ions: Generation and Properties. An Interim Report on PES and ESR Investigations.- Potential Surface Studies of Open Shell Systems.- Computed Physical Properties of Small Molecules.- Calculation of Electronically Excited States in Molecules: Intensity and Vibrational Structure of Spectra, Photochemical Implications.- The Application of Ab Initio Quantum Chemistry to Problems of Current Interest Raised by Experimentalists.- Computer Chemistry Studies of Organic Reactions: The Wolff Rearrangement.- Computer Programs for the Deductive Solution of Chemical Problems on the Basis of Mathematical Models A Systematic Bilateral Approach to Reaction Pathways.- Recent Developments in Computational Chemistry in the U.S.: The NRCC (National Resource for Computation in Chemistry).