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Metastable states of dimethyloxonium, (CH3)2OH⋅
- Source :
-
International Journal of Mass Spectrometry . Jan2003, Vol. 222 Issue 1-3, p49. 13p. - Publication Year :
- 2003
-
Abstract
- Hypervalent dimethyloxonium radical, (CH3)2O&z.sbnd;H⋅ (<B>1</B>), is formed by collisional electron transfer to protonated dimethyl ether in the gas phase and dissociates rapidly by cleavage of the O&z.sbnd;H and O&z.sbnd;C bonds. Ab initio and density functional theory calculations show that these dissociations originate from different electronic states of <B>1</B>. The loss of H proceeds from the repulsive ground electronic (X) state of <B>1</B> and is 131 kJ mol−1 exothermic to form vibrationally excited (CH3)2O. The loss of methyl proceeds from the first excited electronic (A) state of <B>1</B> by crossing to the repulsive part of the X state potential energy surface, yielding vibrationally excited methanol. A substantial fraction of deuterated radicals, (CH3)2O&z.sbnd;D⋅ (<B>1</B>-OD), are metastable on the microsecond time scale. The metastable species result from the population of the B and higher excited states of <B>1</B> that are calculated to be bound along both O&z.sbnd;H and O&z.sbnd;C coordinates. The isotope effects on the metastability of <B>1</B> are explained by less efficient vibronic coupling between the bound B and dissociative A states in the deuterated radical. [Copyright &y& Elsevier]
- Subjects :
- *RADICALS (Chemistry)
*MASS spectrometry
*CHARGE exchange
Subjects
Details
- Language :
- English
- ISSN :
- 13873806
- Volume :
- 222
- Issue :
- 1-3
- Database :
- Academic Search Index
- Journal :
- International Journal of Mass Spectrometry
- Publication Type :
- Academic Journal
- Accession number :
- 8578451