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Double‐valence photoionization of SUVA134a molecule (CFH 2 CF 3 )
Author(s) -
Morcelle Viviane,
Medina Aline,
Ribeiro Leonardo C.,
Prazeres Italo,
Marinho Ricardo R. T.,
Arruda Manuela S.,
Mendes Luis A. V.,
Santos Mabele de Jesus,
Santos Antonio Carlos Fontes dos
Publication year - 2021
Publication title -
rapid communications in mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.528
H-Index - 136
eISSN - 1097-0231
pISSN - 0951-4198
DOI - 10.1002/rcm.9132
Subject(s) - photoionization , chemistry , atomic physics , double ionization , photon energy , ionization , x ray photoelectron spectroscopy , valence (chemistry) , ionization energy , photon , ion , physics , optics , organic chemistry , nuclear magnetic resonance
Rationale In this work we investigate the single‐photon double ionization of the SUVA 134a (1,1,1,2‐tetrafluoroethane) molecule in the energy range from 21.21 to 320 eV. Our experimental data are supported by Thomas’ and Samson's models. It is shown that the double photoionization of the SUVA 134a can be expressed as a sum of the so‐called shake‐off (SO) and the knockout (KO) processes. Methods The experiments were executed at the TGM beamline at Laboratório Nacional de Luz Síncrotron in Campinas, Brazil. The source of EUV and X‐ray radiation was a bending magnet that enabled us to work in the photon energy range of 21.21 to 320 eV. The spectrometer was devised to collect 100% of the ions with kinetic energies up to 30 eV. The photoelectron‐photoion (PEPICO) and photoelectron‐photoion‐photoion (PE2PICO) coincidence techniques were used in the present work. Results The ratio of double‐to‐total photoionization as a function of the photon energy for the SUVA molecule exhibits remarkably similar behavior with other atomic and molecular systems. SO depends on large excess energy above the ionization threshold, enabling the photoelectron to leave the interaction region rather speedily to yield a sudden change in the Coulomb field that the shaken electron feels. The measured asymptotic SO probability is P SO (∞) = 0.09. Conclusions The present analysis shows that the separation of SO and KO processes relies on the experimental evidence that there is no significant interference between SO and KO. The analysis also shows that the separate formulation of KO and SO presents a factual portrayal of double photoionization. Despite having 50 electrons, SUVA has lower double‐to‐total photoionization fraction (9%) in comparison, for instance, to argon atoms (~20%), which has 18 electrons. This lower e‐e correlation could be attributed to its larger volume, that is, lower electron density.