  The impact of spin induced deformation and shape phase transitions on nuclear
level density and consequently on neutron emission spectra of the decay of
compound nuclear systems 112^Ru to 123^Cs (N = 68 isotones) is investigated in
a microscopic framework of Statistical theory of superfluid nuclei. Our
calculations are in good accord with experimental data for evaporation residue
of 119^Sb^* and 185^Re^* and show a strong correlation between spin induced
structural transitions and NLD. We find that the inverse level density
parameter K increases with increasing spin for all the systems, but it
decreases with a deformation or a shape change that results in the enhancement
of level density and emission probability. A sharp shape phase transition from
oblate to uncommon prolate non-collective in well deformed nuclei leads to band
crossing and enhancement of level density which fades away while approaching
sphericity at or near shell closure manifesting shell effects.
