ISSN:
1089-7690
Source:
AIP Digital Archive
Topics:
Physics
,
Chemistry and Pharmacology
Notes:
The C2H photodissociation processes have been studied using ab initio multireference perturbative configuration interaction methods. The calculated structural parameters of the two linear lowest lying states X 2Σ+ and A 2Π were found to be in good agreement with previous theoretical and experimental works. Construction of the correlation diagram indicates that C2H cannot photodissociate into C+CH. Therefore, two-dimensional potential energy surfaces of the six lowest lying A' and A‘ doublet states have been calculated as functions of the bond angle and the C–H bond distance, keeping the C–C distance at the equilibrium C2H value. It appears that the 1 2A', 2 2A', and 1 2A‘ states correlating to the X 2Σ+ and A 2Π states in linear geometry remain bound at all angles, whereas the 3 2A', 4 2A', and 4 2A‘ are dissociative. However, the structure of the energy surfaces is complicated by the presence of numerous avoided crossings between these states. Transition dipole moments connecting the excited states with the X 2Σ+ and A 2Π states have been also obtained in linear geometry. They were calculated to be very weak, leading to the conclusion that the photodissociation rate of C2H will be negligible below 7 eV. Higher lying states, including Rydberg states, were not considered here, since they cannot dissociate directly into C2+H.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1063/1.466654
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