#### Subroutine to Generate Analytic Potential Energy Functions for the X
and A States of CH^{+} and CD^{+}

Cho and Le Roy
[
J.Chem.Phys. 144, 024311 (2016)] determined accurate analytic
potential energy functions for the X(^{1}Σ^{+})
and A(^{1}Π) states of CH^{+} and CD^{+} from
combined-isotopologue direct-potential-fits to all of the available
spectroscopic data. A FORTRAN subroutine for generating
these functions may be downloaded by selecting the link below.
Solution of the Schrodinger equation with these potentials should
use reduced masses based on the masses of the two atoms that
may be incorporated though calls to subroutine 'MASSES.f' from
program **LEVEL** , and a copy of this subroutine being attached to
the PEC subroutine listing. The input parameters for this CH^{+}
potential function subroutine, 'SUBROUTINE POTGEN_CH+XA.f', are the mass
numbers of the isotopologue of interest, an integer identifying which of
the two potentials is to be generated, and the array of radial distances
at which the potential is to be generated. To facilitate use of this
special CH^{+}/CD^{+} potential energy subroutine
in the general-purpose bound-state subroutine LEVEL, an alternate
version this subroutine may be obtained by modifying this subroutine
as described by its internal Comments, with a value of the integer
ISTATE being specified at Line #89.

This subroutine for generating
either of these potentials for either isotopologue is automatically
distributed (by e-mail) to those who fill in the following form:
Download Diatomic CH^{+} Potential Subroutine .

Similarly, sample input data files for performing
program **LEVEL** calculations calculations using
either of these potentials are automatically distributed
(by e-mail) to those who fill in the following form:
Download Diatomic CH^{+} Input data files for
program **LEVEL**.

**Site owned by R.J. Le Roy: leroy @ UWaterloo.ca
**
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