The UV absorption of nucleobases: semi-classical ab initio spectra simulations
Mario Barbatti1, Adelia J A Aquino, Hans Lischka
1Institute for Theoretical Chemistry, University of Vienna, Waehrinegrstrasse 17, A 1090 Vienna, Austria. mario.barbatti@univie.ac.at
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.
Related Concept Videos
UV–Vis Spectroscopy of Conjugated Systems
One of the factors influencing λmax is the extent of conjugation in the...
UV–Vis Spectrum
The UV–Vis spectrum of a molecule is the plot of its absorbance versus wavelength. The plot is drawn by taking molar absorptivity (ε) or log ε on the y-axis (ordinate)...
UV–Vis Spectroscopy: Molecular Electronic Transitions
Ultraviolet and Visible (UV–Vis) Spectroscopy: Overview
Molecular Spectroscopy: Absorption and Emission
UV–Vis Spectrometers


