The ground state of D2Se and HDSe

Ground state rotational constants of (D2Se)-Se-M and (HDSe)-Se-M, M = 76, 7 7, 78, 80, and 82, have been determined up to octic centrifugal distortion terms from ground state combination differences. These were obtained from r otational analyses of the nu(2), nu(1), and nu(3) bands both of natural and Se-80 monoisotopic material recorded with a resolution of ca. 3 x 10(-3) c m(-1). While the full set of rotational parameters of the Se-80 species was determined with significance, some of the centrifugal distortion terms of the less abundant species were either constrained to those of the Se-80 spe cies or extrapotated. (C) 1999 Academic Press.