Experimental verification of the cluster model of CH3F-(ortho-H2)n in solid para-H2 by using mid-infrared pump-probe laser spectroscopy

Abstract

The bleaching process in the C-F stretching mode (ν band) of CHF-(ortho-H) [n = 0 and 1] clusters in solid para-H was monitored using pump and probe laser spectroscopy on the C-H stretching mode (ν and 2ν bands). From an analysis of the depleted spectral profiles, the transition frequency and linewidth of each cluster were directly determined. The results agree with the values previously derived from a deconvolution analysis of the broadened ν/2ν spectrum observed by FTIR spectroscopy. The complementary increase and decrease between the n = 0 and 1 components were also verified through monitoring the ν and 2ν bands, which suggests a closed system among the CHF-(ortho-H) clusters. These observations provide experimental verification of the CHF-(ortho-H) cluster model. On the other hand, a trial to observe the bleaching process by pumping the C-H stretching mode was not successful. This result may be important for understanding the dynamics of vibrational relaxation processes in CHF-(ortho-H) in solid para-H.