Km. Ervin et al., Naphthyl radical: Negative ion photoelectron spectroscopy, Franck-Condon simulation, and thermochemistry, J PHYS CH A, 105(48), 2001, pp. 10822-10831
The naphthyl anion (C10H7-, naphthalenide) is prepared in a flow tube react
or by proton transfer between NH2- and naphthalene (C10H8). The photoelectr
on spectrum of this anion is measured at a fixed laser wavelength of 364 nm
. A single electronic band is observed, corresponding to the neutral naphth
yl radical (C10H7, naphthalenyl). The Franck-Condon profiles for both 1-nap
hthyl (alpha -naphthyl) and 2-naphthyl (beta -naphthyl) are simulated on th
e basis of density functional theory calculations of the vibrational freque
ncies and normal coordinates. Issues involving Franck-Condon simulations fo
r large polyatomic molecules and Duschinsky rotation are discussed. and imp
roved Franck-Condon simulation algorithms are presented. Comparison of the
Franck-Condon simulations with the photoelectron spectrum shows that the ob
served band is predominantly due to the 1-naphthyl isomer, consistent with
previous measurements showing the 1-naphthyl anion as more stable than the
2-naphthyl anion. The observed electron affinity of the 1-naphthyl radical
is EA(0)(1-C10H7) = 1.403 +/- 0.015 eV. On the basis of an evaluation of li
terature data. the recommended gas-phase acidity of naphthalene is Delta H-
acid(298)(1-C10H7-H) = 1649 +/- 14 kJ/mol and the recommended bond dissocia
tion energy of naphthalene is DH298(1-C10H7-H) = 472 +/- 14 kJ/mol.