An Experimental and Theoretical Core-Level Study of Tautomerism in Guanine

• The core level photoemission and near edge X-ray photoabsorption spectra of guanine in the gas phase have been measured and the results interpreted with the aid of high level ab initio calculations. Tautomers are clearly identified spectroscopically, and their relative free energies and Boltzmann populations at the temperature of the experiment (600 K) have been calculated and compared with the experimental results and with previous calculations. We obtain good agreement between experiment and the Boltzmann weighted theoretical photoemission spectra, which allows a quantitative determination of the ratio of oxo to hydroxy tautomer populations. For the photoabsorption spectra, good agreement is found for the C 1s and I 1s spectra but only fair agreement for the N 1s edge.

Ämnesord

NATURVETENSKAP  -- Kemi -- Fysikalisk kemi (hsv//swe)

NATURAL SCIENCES  -- Chemical Sciences -- Physical Chemistry (hsv//eng)

TEKNIK OCH TEKNOLOGIER  -- Elektroteknik och elektronik (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Electrical Engineering, Electronic Engineering, Information Engineering (hsv//eng)

Nyckelord

X-RAY-ABSORPTION

INFRARED-LASER SPECTROSCOPY

ELECTRON BINDING-ENERGIES

GAUSSIAN-BASIS SETS

DNA-BASE GUANINE

GAS-PHASE

AB-INITIO

POLARIZATION PROPAGATOR

GREENS-FUNCTION

ULTRAVIOLET SPECTROSCOPY

Physical chemistry

Fysikalisk kemi

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