title: Ionization and Fragmentation of Formamide Induced by Synchrotron Radiation in the Valence Region via Photoelectron Photoion Coincidence Measurements and Density Functional Theory Calculations.
abstract: We have performed a theoretical and experimental study of the formamide (HCONH2) photofragmentation and photoionization processes in the gas phase. The experiment was perfomed by using a time-of-flight mass spectrometer using the photoelectron photoion coincidence (PEPICO) technique in the valence region, from photons with energy between 10 and 20 eV. We have obtained both mass and partial ion yield spectra, identified by the mass-to-charge ratio as a function of the photon energy. With this setup, we could ascertain the threshold energy for the production of formamide cation and its cationic fragments. The theoretical analysis of the formamide photofragmentation channels are fulfilled by the density functional theory (DFT) and the time-dependent density functional theory (TDDFT). The theoretical analysis allowed us to estimate, for example, which atoms are lost during the photofragmentation. We have also developed a theoretical-experimental analysis of the main fragments produced in the dissociation: m/q = 45 (HCONH2+), m/q = 44 (CONH2+), m/q = 29 (HCO+), m/q = 17 (NH3+), and m/q = 16 (NH2+).
authors.affiliation: Instituto de Física, Universidade Federal da Bahia , 40170-115 Salvador, Bahia, Brazil.|Centro de Ciências Exatas e Tecnológicas, Universidade Federal do Recôncavo da Bahia , 44380-000 Cruz das Almas, Bahia, Brazil.
authors.forename: Manuela S
authors.initials: MS
authors.lastname: Arruda
authors.affiliation: Instituto de Física, Universidade Federal da Bahia , 40170-115 Salvador, Bahia, Brazil.
authors.forename: Aline
authors.initials: A
authors.lastname: Medina
authors.affiliation: Instituto de Física, Universidade Federal da Bahia , 40170-115 Salvador, Bahia, Brazil.
authors.forename: Josenilton N
authors.initials: JN
authors.lastname: Sousa
authors.affiliation: Instituto de Física, Universidade Federal da Bahia , 40170-115 Salvador, Bahia, Brazil.
authors.forename: Luiz A V
authors.initials: LA
authors.lastname: Mendes
authors.affiliation: Instituto de Física, Universidade Federal da Bahia , 40170-115 Salvador, Bahia, Brazil.
authors.forename: Ricardo R T
authors.initials: RR
authors.lastname: Marinho
authors.affiliation: Instituto de Física, Universidade Federal da Bahia , 40170-115 Salvador, Bahia, Brazil.
authors.forename: Frederico V
authors.initials: FV
authors.lastname: Prudente
mesh_terms: D005559:Formamides / Q000737:chemistry*; D056951:Photoelectron Spectroscopy; D017785:Photons; D011789:Quantum Theory; D017356:Synchrotrons
chemical_list: D005559:Formamides; C031066:formamide