A study of the ground and excited states of Al 3 and Al 3 -. II. Computational analysis of the 488 nm anion photoelectron spectrum and a reconsideration of the Al 3 bond dissociation energy

Stephen R. Miller, Nathan E. Schultz, Donald G. Truhlar, Doreen G. Leopold

Research output: Contribution to journalArticlepeer-review

38 Scopus citations

Abstract

Computational results are reported for the ground and low-lying excited electronic states of Al3- and Al3 and compared with the available spectroscopic data. In agreement with previous assignments, the six photodetachment transitions observed in the vibrationally resolved 488 nm photoelectron spectrum of Al 3 - are assigned as arising from the ground X̃ 1A ′ 1 (1A 11) and excited 2B 3 states of Al3- and accessing the ground X̃ A1′2 (A12) and excited A 2″2 ( 2B 1), A24, and B22 states of Al 3 (with C 2v labels for D 3h states in parentheses). Geometries and vibrational frequencies obtained by PBE0 hybrid density functional calculations using the 6-311+G (3d2f) basis set and energies calculated using coupled cluster theory with single and double excitations and a quasiperturbative treatment of connected triple excitations (CCSD(T)) with the aug-cc- pVxZ { x=D, T, Q} basis sets with exponential extrapolation to the complete basis set limit are in good agreement with experiment. Franck-Condon spectra calculated in the harmonic approximation, using either the Sharp-Rosenstock-Chen method which includes Duschinsky rotation or the parallel-mode Hutchisson method, also agree well with the observed spectra. Possible assignments for the higher-energy bands observed in the previously reported UV photoelectron spectra are suggested. Descriptions of the photodetachment transition between the Al 3- and Al 3 ground states in terms of natural bond order (NBO) analyses and total electron density difference distributions are discussed. A reinterpretation of the vibrational structure in the resonant two-photon ionization spectrum of Al 3 is proposed, which supports its original assignment as arising from the X̃ 2A 1′ ground state, giving an Al 3 bond dissociation energy, D0 (Al 2 -Al), of 2.403±0.001 eV. With this reduction by 0.3 eV from the currently recommended value, the present calculated dissociation energies of Al 3, Al 3-, and Al 3+ are consistent with the experimental data.

Original languageEnglish (US)
Article number024304
JournalJournal of Chemical Physics
Volume130
Issue number2
DOIs
StatePublished - 2009

Bibliographical note

Funding Information:
We thank Dr. Michael Morse, Dr. Kent Ervin, and Dr. Susan Green for helpful discussions. This research was supported by the National Science Foundation under Grant No. CHE07-04974 (D.G.T), by the Research Corporation (D.G.L.), and by computer resources provided by the Minnesota Supercomputing Institute.

Fingerprint Dive into the research topics of 'A study of the ground and excited states of Al <sub>3</sub> and Al <sub>3</sub> <sup>-</sup>. II. Computational analysis of the 488 nm anion photoelectron spectrum and a reconsideration of the Al <sub>3</sub> bond dissociation energy'. Together they form a unique fingerprint.

Cite this