Journal of Chemical Physics, Vol.116, No.10, 4162-4169, 2002
Two-photon resonant ionization spectroscopy of the allyl-h(5) and allyl-d(5) radicals: Rydberg states and ionization energies
The vibronic spectra of allyl-h(5) (CH2CHCH2) and allyl-d(5) (CD2CDCD2) radicals at 6.0-8.2 eV have been observed using 2+1 resonance-enhanced multiphoton ionization (REMPI) spectroscopy. The allyl-h(5) and allyl-d(5) radicals were produced in the nozzle of a supersonic jet expansion by the pyrolysis of CH2CHCH2I and CD2CDCD2Br, respectively. Together with our previous study, Rydberg states of ns (n=4-12) for allyl-h(5) and (n=4-10) for allyl-d(5) have been observed in the REMPI spectra. Prominent vibrational progressions with the spacings of similar to440 cm-1 in allyl-h(5) and similar to360 cm-1 in allyl-d(5) are observed in the s Rydberg series. The totally symmetric angleCCC-bending mode is responsible for the vibrational progressions. Facilitated with ab initio calculated Franck-Condon factors, other vibrations (CH2 rocking and C-3 stretching) observed in the s Rydberg series have also been identified. The adiabatic ionization energies, 65 594+/-9 cm(-1) (8.133+/-0.001 eV) for allyl-h(5) and 65 527+/-16 cm(-1) (8.124+/-0.002 eV) for allyl-d(5), are extrapolated from the convergence of the observed ns Rydberg series.