  To discuss whether an enhanced isomer decay is a preferred process in a
plasma environment it is required to know the structure of the isomer as well
as the nearby states. The spin-21/2, 6.85-hour high-spin isomer in 93Mo is
investigated within a shell model which well describes nuclei in this mass
region. By using the obtained wave-functions which correctly reproduce the
observed B(E2), B(E4), and B(M1) transitions, characteristics of the isomer are
shown in comparison with the isomeric states in neighboring nuclei.
Calculations suggest that these high-spin isomers are formed with almost pure
single-particle-like configurations. The 93Mo 21/2^+ isomer has the predominant
configuration $\pi (g_{9/2})^2_{8} \otimes \nu d_{5/2}$ lying below the 15/2^+,
17/2^+, and 19/2^+ states due to neutron-proton interaction, which is the
physical origin of its long lifetime. The key E2 transition that connects the
21/2^+ isomer to the upper 17/2^+ level is predicted to be substantial (3.5
W.u), and therefore there is a real prospect for observing induced isomer
deexcitation.
