The pi --> pi* and n --> 5s absorption spectra of selenoformaldehyde, CH2Se
and CD2Se, are reported. Both spectra are diffuse. The pi --> pi* transiti
on extends from 243 to 210 nm with an extensive Franck-Condon profile and i
ntensity maximum estimated at 230 nm. The Rydberg pi --> 5s transition is s
uperimposed on the n --> pi* system. While still diffuse, the system is les
s extensive and shows an intensity maximum at 235 nm. The corresponding Ryd
berg transition of the deuterated species is blue shifted by 140 cm(-1). (C
) 1999 Academic Press.