A STUDY OF LINEWIDTH AND LINESHAPE: THE APPLICATION OF CONDON MODULATION TO PURE VIBRATIONAL TRANSITIONS OF SOLID HYDROGEN

$^{h}$E. U. Condon, {Phys. Rev}. \textbf{41}, 759 (1932). $^{i}$K. E. Kerr, T. Momose, W.P. Weliky, C. G. Gabrys, and T. Oka, {Phys. Rev. Lett}. \textbf{72}, 3957 (1994).Author Institution: Institute for Astrophysics and Planetary Sciences, Ibaraki University; Department of Chemistry, Department of Astronomy and Astrophysics and the Enrico Fermi institute, The University of ChicagoAs first pointed out by $Condon,^{h}$ a strong electric field can induce new features in the infrared spectra of molecules, which will follow the Raman selection rules. Following our observation of the pure vibrational $Q_{1}(0)$ transition induced by the electric field of ionic species in solid parahydrogen a new modulation technique with much improved sensitivity based on the Condon effect has been $established.^{i}$ Using this technique, we have systematically studied the linewidth frequency shift, and lineshape of the pure vibrational Transitions of samples of parahydrogen crystals (with less than 0.07% of orthohydrogen) at various temperature. Results from this work provide information on the relaxation process in this system, which will lead to a better understanding of the origin of the sharpness of the transitions in solid hydrogens. In this paper, the analysis of our results will be presented