Spectroscopic properties of molecular anions of astrophysical and laboratory interest

Spectroscopic constants and molecular properties of the selected six diatomic anions of astrophysical and laboratory interest namely, FO−, CCl−, NS−, ClO−, ClF− and AlS− in their ground state have been studied in detail using hybrid HF/DF B3LYP method. The effect of basis set on spectroscopic properties has been studied with systematic improvement of basis set from aug-cc-pVDZ to aug-cc-pV5Z. The values of the spectroscopic constants and molecular properties obtained with these basis sets have been extrapolated to the complete basis set (CBS) limit. The spectroscopic properties calculated with the aug-cc-pV5Z basis set are very close to those at the CBS limit and these values agree very well with the theoretical and experimental results wherever available. Many of the spectroscopic constants and molecular properties of these anions are new and in particular those for ClF− and AlS− are first reported.