Probing the spin multiplicity of gas-phase polycyclic aromatic hydrocarbons through their infrared emission spectrum: a theoretical study.
The anharmonic infrared emission spectrum following an optical excitation has been calculated for a variety of polycyclic aromatic hydrocarbon molecules in their ground singlet electronic state or in their triplet state. The computational protocol relies on second-order perturbation theory and involves a quartic vibrational Hamiltonian, the vibrational quantum numbers being sampled according to a Monte Carlo procedure. In the case of neutral naphthalene, the IR spectrum obtained in the (ground) singlet state differs significantly from the spectrum in the triplet state, especially for out-of-plane CH bending modes. Although not as prominent, spectral differences in larger molecules are still observable.
Institut des Sciences Moléculaires d'Orsay, UMR CNRS 8214, Université Paris Sud, F91405 Orsay Cedex, France. cyril.falvo@u-psud.fr
Cyril
C
Falvo
Florent
F
Calvo
Pascal
P
Parneix