A multireference perturbation theory study on the vertical electronic spectrum of thiophene |
| |
Authors: | Mariachiara Pastore Celestino Angeli Renzo Cimiraglia |
| |
Institution: | (1) Dipartimento di Chimica, Università di Ferrara, Via Borsari 46, 44100 Ferrara, Italy |
| |
Abstract: | The vertical electronic spectrum of the thiophene molecule is investigated by means of second and third order multireference
perturbation theory (NEVPT). Single-state and quasi-degenerate NEVPT calculations of more than 25 singlet excited states have
been performed. The study is addressed to the theoretical characterization of the four lowest-energy valence states, as well as the 3s, 3p and 3d Rydberg states. In addition, the excitation energies of two and valence states are also reported. For almost all the excited states, coupled cluster calculations (CCSD and CCSDR(3)) have
been also carried out, using the same geometry and basis set used for the NEVPT ones, in order to make the comparison between
the results of the two methods meaningful. A remarkable accordance between the NEVPT and CC excitation energies is found.
The present results, over all, confirm the experimental assignments but, above all, represent an important contribution to
the assignments of some low-energy states, valence and Rydberg, for which a firm interpretation is not available in the literature. |
| |
Keywords: | Multireference perturbation theory Quasi-degenerate multireference perturbation theory NEVPT Thiophene Five– membered hetero– cycles |
本文献已被 SpringerLink 等数据库收录! |
|