Collisions between a ¹, ², ³Π molecule and a spherical Atom

BASISTYPE = 5

System subroutine: sypi

Basis subroutine: hiba05_pi.F90

Ref. M. H. Alexander, J. Chem. Phys. 76, 5974 (1982); M. H. Alexander, Chem. Phys. 92, 337 (1985); D. Lemoine, G. C. Corey, M. H. Alexander, and J. Derouard, ibid. 118, 357 (1987); G. C. Corey and M. H. Alexander, J. Chem. Phys. 85, 5652 (1986); M. H. Alexander, P. J. Dagdigian, and D. Lemoine, ibid. 95, 5036 (1991).

The definition of the integer system dependent parameters is as follows:

• NTERM: (the number of potential surfaces involved: this should be 3 in this case). This parameter can not be changed

• JMAX: the maximum rotational quantum number of diatomic

  For a ²Π molecule, JMAX is the maximum rotational quantum number minus 1/2; so that the allowed channel rotational angular momenta run from 1/2 to JMAX+1/2.

• IGU: inversion symmetry of states included in expansion
  • IGU = +1 for gerade states (for heteronuclear molecules IGUshould be +1)
  • IGU = -1 for ungerade states

  ⚠️ For heteronuclear molecules (IHOMO = .False.), IGU is ignored but should be set to +1

• ISA: nuclear permutation symmetry (s/a label) of states included in the expansion If the flag IHOMO is .TRUE., then only s states will be included if ISA = +1 and only a states if ISA = -1

• NPAR: number of lambda-doublet components included
  • if NPAR = 1, just ε = +1 states are included
  • if NPAR = 1, both ε = +1 and ε = -1 states are included

• IMULT: spin-multiplicity of Π state (IMULT = 2 S + 1)

• NMAN: number of spin-orbit manifolds included

  For a ²Π state, NMAN = 1 selects the nominally omega = 1/2 manifold in all other cases, NMAN is set equal to IMULT

  The definition of the real system dependent parameters is as follows:

• BROT: rotational constant
• ASO: spin-orbit constant

• O, P, Q: lambda-doubling constants.

  ⚠️ Not all of these parameters are used for the different multiplicities, see the subroutine lib/hibapi.F90