Collisions between a ²Σ Molecule and a Spherical Atom

BASISTYPE = 2

System subroutine: sy2sg

Basis subroutine: hiba02_2sg.F90

Ref. M. H. Alexander, J. Chem. Phys. 76, 3637 (1982).

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

• NTERM: (the number of potential surfaces involved: this should be 2 in this case). This parameter can not be changed
• 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
• NRMAX: maximum Hund’s case (b) rotational quantum number N.
• ISYM: reflection symmetry of electronic state
  • ISYM = +1 for Σ⁺ states
  • ISYM = -1 for Σ^- states
• IGU: inversion symmetry of states included in expansion
  • IGU = +1 for gerade states (for heteronuclear molecules IGUshould be +1)
  • IGU = -1 for ungerade states
• 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

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

• BROT: rotational constant
• GSR: spin-rotation constant
• DROT : centrifugal distortion constant
• HROT: second centrifugal distortion constant