Unexpected rapid variations in odd-even level staggering in gamma-vibrational bands

Triple-γ coincidence data were used to study the γ-vibrational bands to 14+ in 104-106Mo, to 13+ in 108,110Ru and 17+ in 112Ru, and to 13+, 15+ in 112-116Pd. The even-odd spin energy level splittings show rapid variations with spin and neutron number in these nuclides. With one exception, the Sm-Pt nuclei show no such reversal and much smaller staggering.