A-band methyl halide dissociation via electronic curve crossing as studied by electron energy loss spectroscopy.
Excitation of the A-band low-lying electronic states in the methyl halides, CH(3)I, CH(3)Br, CH(3)Cl, and CH(3)F, has been investigated for the (n-->sigma*) transitions, using electron energy loss spectroscopy (EELS) in the range of 3.5-7.5 eV. For the methyl halides, CH(3)I, CH(3)Br, and CH(3)Cl, three components of the Q complex ((3)Q(1), (3)Q(0), and (1)Q(1)) were directly observed, with the exception of methyl fluoride, in the optically forbidden EELS experimental conditions of this investigation. The effect of electronic-state curve crossing emerged in the transition probabilities for the (3)Q(0) and (1)Q(1) states, with spin-orbit splitting observed and quantified against results from recent ab initio studies.
Kato
H
H
Department of Physics, Sophia University, Tokyo 102-8554, Japan.
Masui
H
H
Hoshino
M
M
Cho
H
H
Ingólfsson
O
O
Brunger
M J
MJ
Limão-Vieira
P
P
Tanaka
H
H
D004583:Electrons; D006842:Hydrocarbons, Brominated / Q000737:chemistry*; D006845:Hydrocarbons, Fluorinated / Q000737:chemistry*; D006847:Hydrocarbons, Iodinated / Q000737:chemistry*; D008737:Methyl Chloride / Q000737:chemistry*; D011789:Quantum Theory; D046590:Spectroscopy, Electron Energy-Loss / Q000379:methods*
D006842:Hydrocarbons, Brominated; D006845:Hydrocarbons, Fluorinated; D006847:Hydrocarbons, Iodinated; C029999:fluoromethane; C005218:methyl bromide; D008737:Methyl Chloride; C014055:methyl iodide