
TY  - JOUR
A1  - Beecham, AF 
A1  - Hurley, AC 
A1  - Johnson, CHJ 
T1  - Hydrogen bonding and the n &#8594; p* blue shift in a,b-unsaturated ketones. II. Franck-Condon factors and estimates of the effects of hydrogen bonding on CO bond lengths
JF  - Australian Journal of Chemistry
JO  - Aust. J. Chem.
Y1  - 1980
VL  - 33
IS  - 4
SP  - 699
EP  - 705
KW  - 
UR  - https://doi.org/10.1071/CH9800699 
N2  - Vibrational wave functions and Franck-Condon factors are calculated for the n &#8594; &#960;* transition in &#945;,&#946;-unsaturated ketones by approximating vibrations of the chromophore by those of a diatomic moiety (CO). Comparison of the results with recent c.d. and u.v. absorption measurements indicates that the principal effect of hydrogen bonding on the n &#8594; &#960;* system of these ketones arises from a differential lengthening of the CO bond in the excited electronic state as compared with the ground electronic state. It is these bond length changes which cause (through the Franck-Condon factors) the redistribution of intensity between vibrational sub-bands which is such a striking feature of recent highly resolved c.d. spectra. 
ER  -

