| Autor: |
Kumar S; Atomic and Molecular Collisions Laboratory, CEFITEC-Centre of Physics and Technological Research, Department of Physics, Universidade NOVA de Lisboa, 2829-516 Caparica, Portugal.; Chemical Sciences Division, Lawrence Berkeley National Laboratory, One Cyclotron Road, Berkeley, CA 94720, USA., Hoshino M; Department of Materials and Life Sciences, Sophia University, Tokyo 102-8554, Japan., Kerkeni B; ISAMM, Université de la Manouba, La Manouba 2010, Tunisia.; Département de Physique, LPMC, Faculté des Sciences de Tunis, Université de Tunis el Manar, Tunis 2092, Tunisia., García G; Instituto de Física Fundamental, Consejo Superior de Investigaciones Científicas (CSIC), Serrano 113-bis, 28006 Madrid, Spain., Ouerfelli G; Department of Physics, College of Khurma University, Taif University, P.O. Box 11099, Taif 21944, Saudi Arabia., Al-Mogren MM; Department of Chemistry, College of Sciences, King Saud University, P.O. Box 2455, Ryiadh 11451, Saudi Arabia., Limão-Vieira P; Atomic and Molecular Collisions Laboratory, CEFITEC-Centre of Physics and Technological Research, Department of Physics, Universidade NOVA de Lisboa, 2829-516 Caparica, Portugal. |
| Abstrakt: |
In the present work, we report an update and extension of the previous ion-pair formation study of Hubers, M.M.; Los, J. Chem. Phys. 1975 , 10 , 235-259, noting new fragment anions from time-of-flight mass spectrometry. The branching ratios obtained from the negative ions formed in K + SF 6 collisions, in a wide energy range from 10.7 up to 213.1 eV in the centre-of-mass frame, show that the main anion is assigned to SF 5 - and contributing to more than 70% of the total ion yield, followed by the non-dissociated parent anion SF 6 - and F - . Other less intense anions amounting to <20% are assigned to SF 3 - and F 2 - , while a trace contribution at 32u is tentatively assigned to S - formation, although the rather complex intramolecular energy redistribution within the temporary negative ion is formed during the collision. An energy loss spectrum of potassium cation post-collision is recorded showing features that have been assigned with the help of theoretical calculations. Quantum chemical calculations for the lowest-lying unoccupied molecular orbitals in the presence of a potassium atom are performed to support the experimental findings. Apart from the role of the different resonances participating in the formation of different anions, the role of higher-lying electronic-excited states of Rydberg character are noted. |
