... The Journal of Physical ... 16 For the geometry optimization of the HTFSI molecule, the 6-31G** basis set is used, giving p polarization functions on hydrogen apart from the d functions on the heavy atoms. ... νCS, 788 (11), 794 (7), 790 (9), ν s SNS b, 761 (5), 766 (4), 763 (7), 762 (3), ...