Frequency Domain Laser Spectroscopy

Intermolecular interactions: Structures, vibrations and energetics of van der Waals and hydrogen-bonded complexes and clusters.
UV and IR laser spectroscopy using linear and nonlinear methods, rotational coherence with ultrafast lasers.
Molecular-beam spectroscopy of nucleic acid base pair analogues.Photoinduced proton and hydrogen atom transfer in clusters.

High Resolution Time Domain Laser Spectroscopy

Degenerate four-wave mixing probes molecular states which transitions are covered by the bandwidth of the applied laser fields.
For mostmolecules except H
2 rotational transitions are in the range of tenth of wavenumbers depending on the rotational excitation.The response of the sample is described as a higher order sum of the induced electric polarization vector. For isotropic media the first nonzero term is the 3rd order polarization. The method monitors the evolution of this 3rd order polarization of the sample after an initial alignment of the medium. The experiment itself probes the square of the response function. The signal is dependent of the delay between the pulses and oscillates with a difference frequency of the
states involved.