Knowledge Bank

A new technique for growing good quality molecular crystals suitable for Raman studies at low temperatures has been developed. Crystals of about 1/2 inch diameter and up to 2 inches in length are grown from the melt around a copper rod which is in thermal contact with a refrigerant. Descriptions of liquid helium and nitrogen cryostats for use with the Cary 81 spectrometer will be presented. The Raman spectra of crystals of $NH3,SO2,HCl,HBr$ and $CH4$, grown in this way, will be shown, and their interpretation in terms of crystal field theory briefly discussed.