GAS-PHASE IR-SPECTRUM OF 1-AZAINDOLIZINE - SCALED QUANTUM-MECHANICAL FORCE-FIELD AND SPECTRUM ASSIGNMENT

The gas-phase IR spectrum of 1-azaindolizine has been recorded in the range from 100 to 3200 cm(-1), at the resolution of 0.05 cm(-1), using a multipass cell heated to 80 degrees C. The spectrum analysis has been performed by comparing the experimental spectrum with the theoretical one, using both frequency and intensity matching as guidelines for the assignments. The theoretical spectrum of 1-azaindolizine has been calculated from the harmonic force field evaluated at the self consistent field (SCF) level followed by empirical scaling according to the scaled quantum mechanical (SQM) approach, with pyridine and imidazole as parent molecules. The final root-mean-square deviation (RMSD) of the computed and experimental frequencies is 18 cm(-1).