Franck-Condon factors and vibronic patterns of singlet-triplet transitions of 16O3 molecule falling near the dissociation threshold and above

Abstract The Franck-Condon factors were calculated for vertical electronic transitions between the ground singlet (X1A1) and 3A2, 3B2, and 3B1 excited triplet states associated with the Wulf band of the ozone molecule (O3). The XMCQDPT2 ab initio method including the static and dynamic electronic correlations was used with the aug-cc-pVQZ basis set. Along with the cold bands, a list of the strongest singlet-triplet hot bands falling into the region of the dissociation threshold of O3 is presented. The absorption coefficient simulated for intensities of the electronic-vibrational patterns agrees well with the measured absorbance from literature. In addition, the intensities of the single lines of the electronic-vibrational-rotational transitions were calculated in absolute units for the most pronounced singlet-triplet hot bands located up to the first 3A2(000)←X1A1(000) cold band inclusively. The integrated intensity of the 3A2(000)←X1A1(000) band reported in this work agrees well with the available experimental value from literature.