Knowledge Bank

A sample of $CH2DF$ was prepared in high isotopic purity and the IR spectrum was run on a Bomcm instrument at $0.005cm-1$ resolution. The $v6$ band has strong A-type transitions that could be assigned for J values up to 31; for many lower J some K's up to 10 were also found. There are numerous B-type transitions as well, though with lower intensity. The analysis was based on the A-type transitions and gave a reasonable fit with inclusion of some sextic distortion constants. There is a $(K.K+2)$ Coriolis resonance of $Ka=10$. in this band with $Ka=8$ in the V5 band whose center is some $117cm-1$ higher: the rotational levels cross at about $J=14$. The molecular constants will be compared with those for the symmetrical isotopic molecules, with adjustment for isotopic relationships. This sample was also optically pumped with a $CO2$ laser, and five SMMW laser lines were found. The IR measurements permit assignment of two; however, the other three present more of a problem.