A combined ab initio and Franck–Condon factor simulation study on the photodetachment spectrum of HfO2−
Abstract
Restricted-spin coupled-cluster single-double plus perturbative triple excitation {RCCSD(T)} potential energy functions (PEFs) of the 1A1 state of HfO2 and the
2A1 state of HfO2− were computed, employing the quasi-relativistic effective core potential, ECP60MWB, and an associated contracted [13s6p6d4f3g2h] basis set designed for Hf, and the augmented correlation-consistent polarized valence quadruple-zeta (aug-cc-pVQZ) basis set for O. Based on the differences between the computed r0 and re geometrical parameters obtained from the PEF, and available experimentally derived r0 geometrical parameters of the
1A1 state of HfO2, the experimental re geometrical parameters of the
1A1 state of HfO2 were estimated as:−re(HfO) = 1.7751 Å and θe(OHfO) = 107.37°.
In addition, Franck–Condon factors for the HfO2 ( 1A1) + e← HfO2− (
2A1) electron detachment process, which include allowance for Duschinsky rotation and anharmonicity, were calculated using the computed RCCSD(T) PEFs, and were used to simulate the HfO2 (
1A1) + e← HfO2− (
2A1) photodetachment band of HfO2−. Employing the estimated experimental re geometrical parameters of the
1A1 state of HfO2 obtained in this work, the iterative Franck–Condon analysis (IFCA) procedure was carried out to optimize the geometrical parameters of the
2A1 state of HfO2− until the simulated spectrum matched best with the experimental 355 nm photodetachment
2A1 state of HfO2− derived via the IFCA procedure are re(HfO) = 1.823 Å and θe(OHfO) = 111.5°.
Further calculations on low-lying triplet states of HfO2 gave adiabatic electronic energies (Te’s) of, and vertical excitation energies (Tvert’s) to, the ã 3B2, 3B1,
3A1 and
3A2 states of HfO2 (from the
1A1 state of HfO2), as well as electron affinities (EAs) and vertical detachment energies (VDEs) to these neutral states from the
2A1 state of HfO2−.