His earliest contributions were technological: invention of the continuous carbon monoxidechemical laser in 1969, and development and demonstration of the so-called infrared process of laser isotope separation in the late 1970s. Interests then evolved to more fundamental studies. In the 1980s and 1990s his main contributions were in the areas of unimolecular reactions of polyatomic molecules, and photoinitiated reactions in weakly bound complexes. The latter was acknowledged in 1993 with the Herbert P. Broida Prize in Atomic, Molecular, and Chemical Physics ; together they were acknowledged through the Bourke Lectures and Medal in 2000. Recent research addresses issues in amorphous solid water, photophysics in dopedsuperfluidhelium nanodroplets, complex photochemistry and photophysics of polyatomic molecules, and theories of particle statistics and geometric phases.
Publications
Book chapters
Gas trapping in ice and its release upon warming; A. Bar-Nun, D. Laufer, O. Rebolledo-Mayoral, S. Malyk, H. Reisler, C. Wittig; Solar System Ices, M. Gudipati, editor.
Dynamics of ground state bimolecular reactions; C. Wittig and A.H. Zewail; Atomic and Molecular Clusters, E. Bernstein, editor.
Regioselective photochemistry in weakly bonded complexes; S.K. Shin, Y. Chen, E. Böhmer and C. Wittig; The Dye Laser: 20 Years 57-76.
State resolved simple bond fission reactions: experiment and theory; H. Reisler and C. Wittig; Advances in Kinetics and Dynamics, Vol. 1, J.R. Barker, editor 139-185.
Photoinitiated reactions in weakly bonded complexes: entrance channel specificity; Y. Chen, G. Hoffmann, S.K. Shin, D. Oh, S. Sharpe, Y.P. Zeng, R.A. Beaudet and C. Wittig; Advances in Molecular Vibrations and Collision Dynamics, Vol. 1, Part B, J.M. Bowman, editor 187-229.
NO product state distributions in molecule-surface dissociative scattering: n,i-C3F7NO from MgO; E. Kolodney, P.S. Powers, L. Hodgson, H. Reisler and C. Wittig; Mode Selective Chemistry, J. Jortner et al., editors 443-455.
Photoinitiated reactions in weakly bonded complexes; S.K. Shin, Y. Chen, S. Nickolaisen, S.W. Sharpe, R.A. Beaudet and C. Wittig; Advances in Photochemistry, Vol. 16, D. Volman, G. Hammond and D. Neckers, editors 249-363.
Photodissociation processes in NO-containing molecules; H. Reisler, M. Noble and C. Wittig; Molecular Photodissociation Dynamics, J. Baggott and M.N.R. Ashfold, editors 139-176.
C. Wittig, The Landau-Zener formula, J. Phys. Chem. B 109, 8428.'
J. Underwood, D. Chastaing, S. Lee, and C. Wittig, Heavy hydrides: H2Te ultraviolet photochemistry, J. Chem. Phys. 123, 84312.'
E. Polyakova, D. Stolyarov, and C. Wittig, Multiple photon excitation and ionization of NO in and on helium droplets, J. Chem. Phys. 124, 214308.'
G. Kumi, S. Malyk, S. Hawkins, H. Reisler, and C. Wittig, Amorphous solid water films: Transport and host–guest interactions with CO2 and N2O dopants, J. Phys. Chem. A 110, 2097–2105.'
C. Wittig and I. Bezel, Effective Hamiltonian models and unimolecular decomposition, J. Phys. Chem. B 100, 19850–19860.'
S. Malyk, G. Kumi, H. Reisler, and C. Wittig, Trapping and Release of CO2 guest molecules in amorphous ice, J. Phys. Chem. A 111, 13365–13370.'
C. Wittig, Statistics of indistinguishable particles, J. Phys. Chem. A 113, 7244–7252, Benny Gerber Festschrift.'
L. A. Smith-Freeman, W. H. Schroeder, and C. Wittig, AsH2 ultraviolet photochemistry, J. Phys. Chem. A 113, 2158–2164.'
A. Bar-Nun, D. Laufer, O. Rebolledo-Mayoral, S. Malyk, H. Reisler, C. Wittig, Gas trapping in ice and its release upon warming, Solar System Ices, M. Gudipati, Editor.
C. Wittig, Photon and electron spins, J. Phys. Chem. A113, 15320–15327, Vincenzo Aquilanti Festschrift.