psi4-data 1:0.3-5 / usr / share / psi / samples / psithon1 / input.dat

#! Spectroscopic constants of H2, and the full ci cc-pVTZ level of theory

import diatomic

memory 250 mb

molecule h2{
    H
    H 1 R
}

energies = []
rvals = [0.65, 0.7, 0.75, 0.8, 0.85]
set {
    basis cc-pvtz
    d_convergence 12
    e_convergence 12
    r_convergence 12
}

for r in rvals:
    h2.R = r
    energies.append(energy('fci'))

# Since h2 is the active molecule it will be used by default in diatomic.anharmonicity
# However, if you need to provide the routine a molecule pass it as the third parameter:
#   phys_const = diatomic.anharmonicity(rvals, energies, h2)

phys_consts = diatomic.anharmonicity(rvals, energies)