title: Experimental observation of guanine tautomers with VUV photoionization.
abstract: Two methods of preparing guanine in the gas phase, thermal vaporization and laser desorption, have been investigated. The guanine generated by each method is entrained in a molecular beam, single-photon ionized with tunable VUV synchrotron radiation, and analyzed using reflectron mass spectrometry. The recorded photoionization efficiency (PIE) curves show a dramatic difference for experiments performed via thermal vaporization compared to that with laser desorption. The calculated vertical and adiabatic ionization energies for the eight lowest-lying tautomers of guanine suggest that the experimental observations arise from different tautomers being populated in the two different experimental methods.
authors.forename: Jia
authors.initials: J
authors.lastname: Zhou
authors.forename: Oleg
authors.initials: O
authors.lastname: Kostko
authors.forename: Christophe
authors.initials: C
authors.lastname: Nicolas
authors.forename: Xiaonan
authors.initials: X
authors.lastname: Tang
authors.forename: Leonid
authors.initials: L
authors.lastname: Belau
authors.forename: Mattanjah S
authors.initials: MS
authors.lastname: de Vries
authors.forename: Musahid
authors.initials: M
authors.lastname: Ahmed