The potential energy surface for the electronic ground state of the hydrogen selenide molecule has been determined previously by Jensen and Kozin [J. Mol. Spectrosc. 160 (1993) 39] in a fitting to experimental data by means of the MORBID computer program. We report here a further refinement of this surface, also made with the MORBID program. With the refined potential surface, we can make predictions of rotation-vibration transition wavenumbers for H 2Se, D2Se, and HDSe, and with these predictions we can assign weak spectra of these molecules. We assign here two very weak bands of HD80Se, ν1+ν2+ν3 and 2ν1+ν3. The refinement of the potential energy surface was made possible because (1) the number of vibrational states characterized experimentally for various isotopomers of H2Se has approximately doubled since 1993, and (2) we now have access to larger computers with which we can fit energy spacings of states with J≤8, whereas Jensen and Kozin could only use J≤5. In the present work, we fitted rotation-vibration energy spacings associated with 24 vibrational states of H2 80Se with v1≤6, v2≤3, and v 3≤2; 11 vibrational states of D280Se with v1≤2, v2≤3, and v3≤2, and 17 vibrational states of HD80Se with v1≤3, v 2≤3, and v3≤3. The input data set comprised 3611 energy spacings. In the fitting, we could usefully vary 29 potential energy parameters. The standard deviation of the fitting was 0.12cm-1 and the root-mean-square deviation for 49 vibrational term values was 0.59cm -1.
ASJC Scopus subject areas
- Atomic and Molecular Physics, and Optics
- Physical and Theoretical Chemistry