title: The UV absorption of nucleobases: semi-classical ab initio spectra simulations.
abstract: Semi-classical simulations of the UV-photoabsorption cross sections of adenine, guanine, cytosine, thymine, and uracil in gas phase were performed at the resolution-of-identity coupled cluster to the second-order (RI-CC2) level. With the exception of cytosine, the spectra of the other four nucleobases show a two band pattern separated by a low intensity region. The spectrum of cytosine is shaped by a sequence of three bands of increasing intensity. The first band of guanine is composed by two pipi* transitions of similar intensities. The analysis of individual contributions to the spectra allows a detailed assignment of bands. It is shown that the semi-classical simulations are able to predict general features of the experimental spectra, including their absolute intensities.
authors.affiliation: Institute for Theoretical Chemistry, University of Vienna, Waehrinegrstrasse 17, A 1090 Vienna, Austria. mario.barbatti@univie.ac.at
authors.forename: Mario
authors.initials: M
authors.lastname: Barbatti
authors.forename: Adelia J A
authors.initials: AJ
authors.lastname: Aquino
authors.forename: Hans
authors.initials: H
authors.lastname: Lischka
mesh_terms: D000042:Absorption; D000225:Adenine / Q000737:chemistry; D003596:Cytosine / Q000737:chemistry; D005740:Gases / Q000737:chemistry; D006147:Guanine / Q000737:chemistry; D009705:Nucleosides / Q000737:chemistry*; D011789:Quantum Theory; D013056:Spectrophotometry, Ultraviolet; D013941:Thymine / Q000737:chemistry; D014498:Uracil / Q000737:chemistry
chemical_list: D005740:Gases; D009705:Nucleosides; D014498:Uracil; D006147:Guanine; D003596:Cytosine; D000225:Adenine; D013941:Thymine