An interpretation of the absorption and emission spectra of the gold dimer using modern theoretical tools

Abstract

The excited states of the gold dimer have been investigated using modern theoretical tools including the multiconfigurational exact molecular mean-field intermediate Hamiltonian Fock-space Coupled Cluster, X2Cmmf-IHFSCC, and the complete active space self-consistent field followed by second order perturbation theory, CASSCF/CASPT2. The computed optically active transitions have been benchmarked against the available experimental data and compared with time-dependent density functional theory, TDDFT, results, both in the two- and four-component schemes. We explored in great detail several spectroscopic properties such as bond lengths, potential energy surfaces (PES), vibrational frequencies and vibrational progressions of the ground and low-lying excited states. Our data show excellent agreement with the experimental measurements and present a significant improvement compared to previous ab initio calculations. They also permit a detailed investigation of the intriguing a ← X and A'← X experimental bands that, according to our calculations, show an avoided energy level crossing. The location of this crossing is critical for a correct estimation of the vibrational progression and oscillator strengths of these two states. Moreover, among the exchange-correlation (xc) potentials, the SAOP gives the best excitation energies, followed by the hybrid B3LYP functional. Pure functionals like BLYP give by far the worst results.

The Nature and Role of the Gold–Krypton Interactions in Small Neutral Gold Clusters

“…84 This would also be consistent with the value reported by Ghiringhelli et al, 35 of 200 cm −1 using CCSD(T). A recent study of the bare gold dimer by Geethalakshmi et al 81 using high level ab initio methods shows a value for the vibrational frequency of the ground state that is in very good agreement with the experimental value reported by Ruamps.…”

High resolution photoelectron imaging of Au2−

“…Au 2 − was a) E-mail: Lai-Sheng_Wang@brown.edu selected because of its well-known spectroscopy. 7,[27][28][29][30][31][32][33] In particular, a vibrationally resolved PES spectrum of Au 2 − was first reported by Lineberger and co-workers using a hemispherical electron analyzer at a resolution of ∼6 meV and a vibrational temperature of 350 ± 25 K. 28 Gantefor and coworkers reported a ZEKE spectrum of Au 2 − in the photon energy range of 1.85 to 2.025 eV at a spectral resolution of 1.5 meV and a vibrational temperature of 165 ± 30 K. 7 In the current work, we report photoelectron images of Au 2 − in the photon energy range of 1.8470 eV (671.28 nm) to 2.8000 eV (442.80 nm) at a vibrational temperature of 175 ± 25 K and a kinetic energy resolution of 2.8 cm −1 for slow electrons.…”

TD-DFT benchmarks: A review

“…In that Table, like in the following of this review, we have mainly selected benchmarks that considered at least three XCF and a diverse set of compounds. Indeed, though one could find a number of studies that considered only one functional applied on a large set of molecules, [121][122][123][124][125][126][127][128][129][130][131][132] or tested a large number of XCF but on a rather specific family of compounds, [97,[133][134][135][136][137][138][139][140][141][142][143][144][145][146][147][148] these works are often rather specific and the obtained conclusions are sometimes difficult to generalize. We nevertheless briefly summarized a number of them in this review.…”