Basis Subroutine and System Specific Parameters: Collision of an Atom with a Symmetric Top

System subroutine: systp

Basis subroutine: hibastp.f

Ref. S. Green, J. Chem. Phys. 64, 3463 (1976); 67, 816 (1979).

NTERM (the number of potential surfaces involved: this should be 1 in this case). This parameter can not be changed

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 NH₃, IPOTSY = 3

IOP: ortho/para label for molecular states of symmetric top. If IHOMO =.true. then

if IOP = 1: only para states included in channel expansion
if IOP = -1: only ortho states included in channel expansion

NINV: number of inversion doublets included

if NINV = +1, only + inversion levels included
if NINV = -1, only - inversion levels included
if NINV = 2, both inversion levels included

KMAX: the maximum projection quantum number included

JMAX0: the maximum rotational angular momenta for the k = 0 stack

JMAX1: the maximum rotational angular momenta for the k = 1 stack

JMAX2: the maximum rotational angular momenta for the k = 2 stack

JMAX3: the maximum rotational angular momenta for the k = 3 stack

JMAX4: the maximum rotational angular momenta for the k = 4 stack

JMAX5: the maximum rotational angular momenta for the k = 5 stack

JMAX6: the maximum rotational angular momenta for the k = 6 stack

JMAX7: the maximum rotational angular momenta for the k = 7 stack

JMAX8: the maximum rotational angular momenta for the k = 8 stack

JMAX9: the maximum rotational angular momenta for the k = 9 stack

JMAX10: the maximum rotational angular momenta for the k = 10 stack

JMAX11: the maximum rotational angular momenta for the k = 11 stack

BROT, CROT: rotational constants of symmetric top, so that
E(jk) = BROT j (j + 1) + (CROT - BROT) k²