		15min:

OBSERVATION OF NEW INFRARED TRANSITIONS IN SOLID PARAHYDROGEN.

M. MENGEL, B. P. WINNEWISSER AND M. WINNEWISSER, Physikalisch-Chemisches Institut, Justus-Liebig-Universität, Heinrich-Buff-Ring 58, D-35392 Giessen, Germany.

In recent measurements of infrared transitions in solid parahydrogen with low ortho impurities, using an internal multireflection system for a sample path length of 14 cm, we have detected new weak features in the spectral region 10\,000--13\,000 cm^-1. Of particular interest here is the second overtone band of solid hydrogen and double transitions of the type Q₂(J') + Q₁(J) (J,J'=0,1) which will be presented. At 10\,241.07 cm^-1 the new single transition W₂(0) could be observed.

We will also present further results of the analysis of our measurements in the first overtone region, especially a theoretical explanation of the intensities in the fine structure of the Q₁(1) + Q₁(1) double transition.

The absorption spectrum in the mid-infrared region (700--2\,000 cm^-1) is currently under investigation, and new information in this region will also be presented.