title: A VUV Photoionization and Ab Initio Determination of the Ionization Energy of a Gas-Phase Sugar (Deoxyribose).
abstract: The ionization energy of gas-phase deoxyribose was determined using tunable vacuum ultraviolet synchrotron radiation coupled to an effusive thermal source. Adiabatic and vertical ionization energies of the ground and first four excited states of α-pyranose, the structure that dominates in the gas phase, were calculated using high-level electronic structure methods. An appearance energy of 9.1(±0.05) eV was recorded, which agrees reasonably well with a theoretical value of 8.8 eV for the adiabatic ionization energy. A clear picture of the dissociative photoionization dynamics of deoxyribose emerges from the fragmentation pattern recorded using mass spectrometry and from ab initio molecular dynamics calculations. The experimental threshold 9.4 (±0.05) eV for neutral water elimination upon ionization is captured well in the calculations, and qualitative insights are provided by molecular orbital analysis and molecular dynamics snapshots along the reaction coordinate.
authors.affiliation: Department of Chemistry, University of Southern California , Los Angeles, California 90089-0482, United States.
authors.forename: Debashree
authors.initials: D
authors.lastname: Ghosh
authors.affiliation: Chemical Sciences Division, Lawrence Berkeley National Laboratory , Berkeley, California 94720, United States.
authors.forename: Amir
authors.initials: A
authors.lastname: Golan
authors.affiliation: Chemical Sciences Division, Lawrence Berkeley National Laboratory , Berkeley, California 94720, United States.|Department of Chemistry, University of California at Berkeley , Berkeley, California 94720, United States.
authors.forename: Lynelle K
authors.initials: LK
authors.lastname: Takahashi
authors.affiliation: Department of Chemistry, University of Southern California , Los Angeles, California 90089-0482, United States.
authors.forename: Anna I
authors.initials: AI
authors.lastname: Krylov
authors.affiliation: Chemical Sciences Division, Lawrence Berkeley National Laboratory , Berkeley, California 94720, United States.
authors.forename: Musahid
authors.initials: M
authors.lastname: Ahmed
keywords: electronic structure calculations; fragmentation; mass spectrometry; sugars; synchrotron radiation