Optical to ultraviolet spectra of sandwiches of benzene and transition metal atoms: Time dependent density functional theory and many-body calculations

Abstract

The optical spectra of sandwich clusters formed by transition metal atoms ͑titanium, vanadium, and chromium͒ intercalated between parallel benzene molecules have been studied by time-dependent density functional theory ͑TDDFT͒ and many-body perturbation theory. Sandwiches with different number of layers, including infinite chains, are considered. The lowest excitation energy peaks in the spectra are characteristic of the robust bonding in these complexes. The excitation energies vary in a systematic way with the metal atoms and with the cluster size, and so these materials could be used to tune the optical properties according to specific functionality targets. The differences in the spectra could be used to identify relative abundances of isomers with different spins in experimental studies. As a salient feature, this theoretical spectroscopic analysis predicts the metallization of the infinite ͑TiBz͒ ϱ chain, which is not the case of ͑CrBz͒ ϱ .

Luminescent Cyclometalated Platinum Complexes with π-Bonded Catecholate Organometallic Ligands

“…The investigation of the structures and electronic properties of their singlet excited states was carried out by means of the hybrid exchange-correlation functional PBE0, 44,45 which was already successfully employed in the case of sandwich complexes. [68][69][70][71] The charge distribution within the complexes was investigated with the natural bond orbital (NBO) population analysis program (NBO program version 3.1). 49,50 Besides, the information obtained by the long-range corrected hybrid functional LC-ωPBE [51][52][53] was also considered to correctly describe the asymptotic behavior of the functional, which is important in the case of charge transfer (CT) transitions.…”

Theoretical Study of the Structural Stability and the Electronic Properties of Al<SUB>m</SUB>H<SUB>n</SUB> Clusters

“…Our previous use of this functional gave satisfactory results. 18 In all cases, the structural relaxations have been performed with a steepest-descent algorithm and a convergence criterion of 10 −2 eV/Å for the net force on every atom. All the atoms are free to move along the structural relaxation processes.…”

Nuclear Shell Structure in a Finite-Temperature Relativistic Framework

“…The equation of motion (EOM) method builds a systematic framework for the description of many-body correlations, in particular, in strongly coupled fermionic systems [14][15][16][17][18][19]. Within this framework, the EOM's are generated for various time-dependent quantities, such as the correlation functions of field operators.…”

“…Needless to say, such approximations neglect the explicit coupling between the one-body and two-body EOM's and, thus, are insufficient for an accurate description of nuclear phenomena, which is required for modern applications and for a deep understanding of emergent effects. A better accuracy can be achieved by cluster expansions of the dynamical kernels of both the one-body and twobody fermionic EOM's in terms of the two-time two-body correlation functions, as it is discussed, e.g., in the context of the condensed matter and quantum chemistry applications [14][15][16]18]. For the nuclear physics calculations, possible truncation schemes of the dynamical kernels on the two-body level were discussed, in particular, in Ref.…”