Rf. Gunion et al., PHOTOELECTRON-SPECTROSCOPY OF C4H4- - AB-INITIO CALCULATIONS AND DYNAMICS OF THE 1,2-HYDROGEN SHIFT IN VINYLVINYLIDENE, The Journal of chemical physics, 103(4), 1995, pp. 1250-1262
The ultraviolet photoelectron spectrum of HXC=C- (X=C2H3) is reported
along with Qb initio calculations. The adiabatic electron affinity of
the X(1)A' state is measured to be 0.914(15) eV for C4H4 and 0.909(15)
eV for C4D4. The term energy of the C4H4 a ($) over tilde(3) A' state
is 1.923(15) eV and the b (3)A '' term energy is 2.035(30) eV. Geomet
ries and frequencies of several stationary points on the C4H4 and C4D4
neutral and anion surfaces at the configuration interaction with sing
les and doubles level. of theory are reported, as well as an intrinsic
reaction coordinate calculation at the restricted Hartree Fock level
on the C4H4 Singlet surface. Calculations and experiment are combined
to estimate the lifetime of singlet vinylvinylidene for rearrangement
to vinylacetylene to be 20-200 fs, corresponding to lifetime broadenin
g of 35-3 meV. (C) 1995 American Institute of Physics.