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High-resolution Rotational Raman Coherence Spectroscopy with Femtosecond Pulses

  1. Hans-Martin Frey,
  2. Dominique Kummli,
  3. Simon Lobsiger,
  4. Samuel Leutwyler

Published Online: 15 SEP 2011

DOI: 10.1002/9780470749593.hrs055

Handbook of High-resolution Spectroscopy

Handbook of High-resolution Spectroscopy

How to Cite

Frey, H.-M., Kummli, D., Lobsiger, S. and Leutwyler, S. 2011. High-resolution Rotational Raman Coherence Spectroscopy with Femtosecond Pulses. Handbook of High-resolution Spectroscopy. .

Author Information

  1. Universität Bern, Departement für Chemie und Biochemie, Bern, Switzerland

Publication History

  1. Published Online: 15 SEP 2011

Abstract

Femtosecond time-resolved rotational coherence spectroscopy (RCS), when applied in a Raman scattering version, can be utilized for the measurement of highly accurate rotational and centrifugal constants of ground and vibrationally excited states of nonpolar molecules. A brief outline of the theoretical background is given, including the basics of rotational coherence spectroscopy, nonlinear optical four-wave mixing (FWM), molecular polarizability, the rotational Raman process, nuclear spin statistics, and collisional dephasing. An experimental setup for femtosecond rotational Raman RCS measurements is described, featuring some of the points necessary to achieve high experimental accuracy. Rotational Raman RCS spectroscopy has been performed on a number of nonpolar linear and symmetric-top molecules. The examples presented here (CS2, cyclobutane, and cyclooctatetraene) are selected to show the scope of the method and currently achievable accuracy of the rotational and the centrifugal distortion constants, as well as the detailed considerations necessary to achieve these results. The last section reviews a procedure for the determination of semiexperimental equilibrium structures.

Keywords:

  • rotational coherence spectroscopy;
  • rotational Raman;
  • time-resolved Raman scattering;
  • molecular equilibrium geometry;
  • structure