Rj. Horwitz et al., PHOTOFRAGMENTATION OF ACETYL CYANIDE AT 193 NM, The journal of physical chemistry. A, Molecules, spectroscopy, kinetics, environment, & general theory, 101(7), 1997, pp. 1231-1237
The photodissociation of gaseous acetyl cyanide has been examined foll
owing excitation at 193 nm. CN X(2) Sigma(+) photofragments were probe
d via laser fluorescence excitation to determine their rotational, vib
rational, and translational energy distributions. CN was produced in v
'' = 0 and 1 with mean rotational energy (13.5 +/- 2) kJ mol(-1), and
v'' = 2 with mean rotational energy (10 +/- 4) kJ mol(-1). Mean transl
ational energies of the CN fragments were (32 +/- 10) kJ mol(-1). Ab i
nitio electronic structure theory has been used to characterize the he
at of formation for acetyl cyanide along with its geometries and vibra
tional frequencies. The acetyl cyanide heat of formation, Delta H0(f,0
), is predicted to be (-0.4 +/- 8) kJ mol(-1) using Gaussian-2 theory
(G2). The theoretical results are used to compute bond dissociation en
ergies of acetyl cyanide for further interpretation of the experimenta
l photodissociation data. Evidence is presented that the majority of C
N fragments are produced via dissociation of the parent acetyl cyanide
to CH3CO + CN, with subsequent decomposition of the acetyl fragment.
The alternate possible primary alpha-cleavage pathway to CH3 + OCCN is
proposed as a possible source for the OCCN radical.