Near Hartree-Fock calculations on I2 and its positive and negative ions
Abstract
Potential curves from single configuration SCF calculations near the complete basis set limit are reported for ground state I2( 1Σ+), ground state I2-( 2Σ+), and the lowest I2+( 2Φ) and I2+(2Σ +) states. Orbitals are expanded in a Slater basis; the Hamiltonian is the usual nonrelativistic one with no spin-orbit and other relativistic effects. The calculations are done to provide a benchmark for model-potential, multiconfiguration, and relativistic and spin-orbit studies. The effect of performing calculations in a symmetry lower than that of the nuclear frame is discussed, and the unusual example of two stable SCF solutions at a given nuclear separation, both computed in the lower symmetry, is demonstrated for I2+(2Π). An experimental value for D e(I2-) of 1.07±0.1 eV is derived; compared with the Hartree-Fock computed value of 0.60J±0.05 eV. Potential curves are analysed for spectroscopic constants. The Hartree-Fock electron affinity of I2 is 2.17±0.1 eV compared with observed 2.58±0.1 eV. The Hartree-Fock quadrupole moment of the I2 molecule in its ground state is 6.24x10-26 esu cm2. © 1980 American Institute of Physics.