The mass distributions of fission fragments from the reaction Th-232(n
,f) are studied in the neutron-energy range from 1.14 MeV to 3.5 MeV.
The probabilities of the standard-valley population are found to be st
rongly correlated with the resonances of the fission cross section. Th
e mass mode in the region of m = 140 amu (the second standard mode) ca
n be realized only via the K = 1/2 rotational band, whereas the first
standard mode (m similar or equal to 134 amu) can be associated with t
he K = 1/2 and K = 3/2 bands.