Vibrational overtone excitation of the first (a) and second (b) overtone of the C–H stretch region of pyrrole: (i) measured room-temperature photoacoustic (PA) absorption spectrum, (ii) measured jet-cooled action spectrum monitoring the H photofragments yield, following 243.135 nm photodissociation of vibrationally excited molecules, (iii) simulated action spectrum, showing the contribution of different bands, and (iv) stick spectrum, where the positions reflect the origins of the bands and the heights represent the fractional contributions of the pure local-mode basis states, derived from the vibrational Hamiltonian. Trace (ii) also includes the band numbers and their assignment is given in Table II , based on the parameters of Table I .
Equilibrium structure of pyrrole with the selected numbering for the C–H stretches.
Time dependent populations of the zero-order bright states |2 0 0 0⟩ and |0 2 0 0⟩ (a) and |3 0 0 0⟩ and |0 3 0 0⟩ (b) and the corresponding doorway states, as determined from the simplified LM/NM Hamiltonian for the coupled C–H stretches and deformations in pyrrole and taking in account the homogeneous broadening.
Best-fit parameters in cm−1 for the C–H stretching manifolds of pyrrole, accounting for the involved Fermi resonances.
Observed band positions and assignments of the pyrrole C–H stretch overtone regions in terms of the joint local-/normal-mode model.
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