RF02		10min1:47

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

In our most recent measurements of infrared transitions of solid parahydrogen with low ortho impurities, using a White-type external multireflection system for a sample path length of 38 cm, we have detected new extremely weak features in the spectral region 7900 - 9900 cm^-1. Among them are the single transition \beginitemize em Y_{1<- 0}(0) at 7991.85~(1) cm^-1 \enditemize and the double transitions \beginitemize em Q_{1<- 0}(0) + Q_{1<- 0}(0) at 8306.0~(1) cm^-1 em U_{1<- 0}(0) + Q_{1<- 0}(1) at 9407.67~(5) cm^-1 em Q_{1<- 0}(0) + S_{1<- 0}(0) at 9747.8~(1) cm^-1 em U_{1<- 0}(1) + Q_{1<- 0}(0) at 9837.34~(5) cm^-1. \enditemize The Y_{1<- 0}(0) transition is the second transition with J = 8 observed in a molecular spectrum after the Y_{0<- 0}(0) transition and is even weaker than the latter by an appreciable factor. Intensity parameters will be reported for all of these transitions. The data were taken at a sample temperature of 12.3 K.