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Szmytkowski C, Stefanowska S, Zawadzki M, Ptasińska-Denga E, Możejko P. Electron collisions with methyl-substituted ethylenes: Cross section measurements and calculations for 2-methyl-2-butene and 2,3-dimethyl-2-butene. J Chem Phys 2015; 143:064306. [PMID: 26277137 DOI: 10.1063/1.4927703] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
We report electron-scattering cross sections determined for 2-methyl-2-butene [(H3C)HC = C(CH3)2] and 2,3-dimethyl-2-butene [(H3C)2C = C(CH3)2] molecules. Absolute grand-total cross sections (TCSs) were measured for incident electron energies in the 0.5-300 eV range, using a linear electron-transmission technique. The experimental TCS energy dependences for the both targets appear to be very similar with respect to the shape. In each TCS curve, three features are discernible: the resonant-like structure located around 2.6-2.7 eV, the broad distinct enhancement peaking near 8.5 eV, and a weak hump in the vicinity of 24 eV. Theoretical integral elastic (ECS) and ionization (ICS) cross sections were computed up to 3 keV by means of the additivity rule (AR) approximation and the binary-encounter-Bethe method, respectively. Their sums, (ECS+ICS), are in a reasonable agreement with the respective measured TCSs. To examine the effect of methylation of hydrogen sides in the ethylene [H2C = CH2] molecule on the TCS, we compared the TCS energy curves for the sequence of methylated ethylenes: propene [H2C = CH(CH3)], 2-methylpropene [H2C = C(CH3)2], 2-methyl-2-butene [(H3C)HC = C(CH3)2], and 2,3-dimethyl-2-butene [(H3C)2C = C(CH3)2], measured in the same laboratory. Moreover, the isomeric effect is also discussed for the C5H10 and C6H12 compounds.
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Affiliation(s)
- Czesław Szmytkowski
- Department of Atomic, Molecular and Optical Physics, Faculty of Applied Physics and Mathematics, Atomic Physics Group, Gdańsk University of Technology, ul. G. Narutowicza 11/12, 80-233 Gdańsk, Poland
| | - Sylwia Stefanowska
- Department of Atomic, Molecular and Optical Physics, Faculty of Applied Physics and Mathematics, Atomic Physics Group, Gdańsk University of Technology, ul. G. Narutowicza 11/12, 80-233 Gdańsk, Poland
| | - Mateusz Zawadzki
- Department of Atomic, Molecular and Optical Physics, Faculty of Applied Physics and Mathematics, Atomic Physics Group, Gdańsk University of Technology, ul. G. Narutowicza 11/12, 80-233 Gdańsk, Poland
| | - Elżbieta Ptasińska-Denga
- Department of Atomic, Molecular and Optical Physics, Faculty of Applied Physics and Mathematics, Atomic Physics Group, Gdańsk University of Technology, ul. G. Narutowicza 11/12, 80-233 Gdańsk, Poland
| | - Paweł Możejko
- Department of Atomic, Molecular and Optical Physics, Faculty of Applied Physics and Mathematics, Atomic Physics Group, Gdańsk University of Technology, ul. G. Narutowicza 11/12, 80-233 Gdańsk, Poland
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