PNNL

Abstract

The direct photodetachment and two-photon dissociation-photodetachment processes of a series of PtIn¯ (n=2-5) anions were systematically studied using cryogenic anion photoelectron spectroscopy and first principle electronic structure calculations. The adiabatic/vertical detachment energies (ADE/VDE) of these anions were determined from their 193 nm photoelectron (PE) spectra, i.e., 3.54/3.63, 4.04/4.09, 4.33/4.36, 4.37/4.41 eV for n = 2-5, respectively, and well reproduced by B3LYP-D3(BJ)/aug-ccpVTZ- pp calculations. As the coordination number increases, the electron affinity (EA) of PtIn • (n=2-5) neutrals (equivalent to the corresponding anion’s ADE) gradually increases, exceeding the EA of Cl at n = 3 and exhibiting super-halogen characteristics for n = 3. Meanwhile, the ground state transition contributed from detaching electrons in the highest occupied molecular orbital (HOMO) gradually evolves from the central metal Pt to the iodine ligands. For the PtI3¯ anion, besides one-photon direct detachment, four distinct two-photon dissociation-photodetachment channels were identified, and the competition between them was discussed.