Origin of Resonant Character in the Electron Impact Two-Body Neutral-Fragmentation of Methane |
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Authors: | Dr Y Sajeev Dr Daly Davis Dr Sramana Kundu Prof Vaibhav S Prabhudesai Prof E Krishnakumar |
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Institution: | 1. Theoretical Chemistry Section, Bhabha Atomic Research Centre, Mumbai, 400085 India;2. S K Somaiya College, Somaiya Vidhyavihar University, Mumbai, 400077 India;3. Department of Nuclear and Atomic Physics, Tata Institute of Fundamental Research, Mumbai, 400005 India;4. Raman Research Institute, Sadashivanagar, Bangalore, 560080 India |
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Abstract: | The observation of peaks in the threshold region of two-body neutral fragmentation of methane molecule, i. e., CH4→CH3+H, by low energy electron (LEE) impact has been an enigma. The prevailing explanation that this resonant behavior is due to excitation energy transfer is unsatisfactory since this process is not expected to show peaks in the cross-sections unless there is the involvement of electron-molecule resonances. Our first-principles calculations now reveal that the observed peaks could be explained as due to the formation of negative ion resonances, which dominantly dissociate into two neutral fragments and a free-electron. This case of methane is a pointer to the possibility that such reactions contribute significantly to neutral radical production from molecules by LEE impact in comparison to dissociative electron attachment, and in general could play a significant role in electron-based chemical control. |
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Keywords: | bond breaking by catalytic electron low energy electron neutral fragmentation resonant electron attachment coupled cluster calculations |
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