title: The electron affinities of the radicals formed by the loss of an aromatic hydrogen atom from adenine, guanine, cytosine, uracil, and thymine.
abstract: The major ion formed in Negative Ion Chemical Ionization Mass Spectrometry of Adenine, Guanine, Cytosine, Uracil and Thymine is the dehydrogenated anion. The CURES EC procedure for optimizing Austin Model-1 Multiconfigurational Configuration Interaction semi-empirical calculations is applied to the electron affinities of the corresponding dehydrogenated bases and N-H bond dissociation energies. These calculated values will be compared with literature values of the gas phase acidities of the purines and pyrimidines. The N-H bond dissociation energies are about 3.95 eV for Guanine, Adenine, and Thymine and 4.08 eV for Cytosine and Uracil. The electron affinities of the radicals are AMinH = 3.50 eV, GMinH = 3.46 eV, CMinH = 3.38 eV, UMinH = 3.48 eV, TMinH = 3.46 eV.
authors.affiliation: Center for Research in Parallel Computing, Rice University, Houston, Texas 77005, USA.
authors.forename: E S
authors.initials: ES
authors.lastname: Chen
authors.forename: E C
authors.initials: EC
authors.lastname: Chen
authors.forename: N
authors.initials: N
authors.lastname: Sane
mesh_terms: D000225:Adenine / Q000737:chemistry; D003596:Cytosine / Q000737:chemistry; D004563:Electrochemistry; D005609:Free Radicals / Q000737:chemistry; D006147:Guanine / Q000737:chemistry; D006859:Hydrogen / Q000737:chemistry; D013058:Mass Spectrometry; D011687:Purines / Q000737:chemistry*; D011743:Pyrimidines / Q000737:chemistry*; D013816:Thermodynamics; D013941:Thymine / Q000737:chemistry; D014498:Uracil / Q000737:chemistry
chemical_list: D005609:Free Radicals; D011687:Purines; D011743:Pyrimidines; D014498:Uracil; D006147:Guanine; D006859:Hydrogen; D003596:Cytosine; D000225:Adenine; D013941:Thymine