PHOTOABSORPTION AND FLUORESCENCE EXCITATION OF MALONONITRILE IN THE VACUUM UV REGION

The cross-sections for the photoabsorption and fluorescence excitation of CH2(CN)(2) were measured in the 105-200 nm region using synchrotro n radiation. The absorption bands were interpreted in terms of the tra nsitions to the valence and Rydberg states. The vibrational progressio ns observed in the Rydberg bands were assigned on the basis of ab init io MO calculations. CN(B-2 Sigma(+)) and CN(A(2)II(i)) photofragments were identified by a dispersed fluorescence spectrum. The fluorescence quantum yields for CN(B-2 Sigma(+)) and CN(A(2)II(i)) formation incre ase with decreasing excitation wavelengths. The CN(B-2 Sigma(+)) quant um yield has a maximum of 0.85% at 107 nm. (C) 1998 Elsevier Science B .V.