The absorption spectrum of a supersonically expanded beam of methanol in the vacuum ultraviolet region

The vacuum ultraviolet absorption spectrum of methanol and two of its isotopes was recorded in the region 60 000-70 000 cm(-1). The molecules were supersonically expanded and they absorbed the impinging photons 1-2 cm downstream from the pulsed nozzle. The sharp peaks indicate an efficient cooling process. However, we could not detect any new peaks associated with dimers or higher oligomers. We assign the observed peaks as transition to the 3p Rydberg states. (C) 1996 Academic Press, Inc.