Basis subroutine: hibastp1.f
Ref. S. Green, J. Chem. Phys. 64, 3463 (1976); M. H. Alexander, J. Chem. Phys. 77, 1855 (1982).
NUMPOT: an index representing the particular potential used. This variable is passed to the POT subroutine
IPOTSY: cylindrical symmetry of potential. If the flag IHOMO = .true., only terms with mu equal to an integer multiple of IPOTSY can be included in the potential. Example: for CH3, IPOTSY = 3
IOP: ortho/para label for molecular states of symmetric top. If IHOMO =.true. then
JMAX: the maximum rotational angular momentum included in the channel expansion
EMAX: the maximum energy of a state to be included in the rotational state basis