New shifts have been investigated for the gamma-ray emitted from nucle
i placed between two parallel plates. The theoretical result of the sh
ift is -2.13 x 10(-8) eV with a plate separation b = 1 mm for the tran
sition from the ground state to the first excited state of Ir-193. The
preliminary experimental result is (-0.23 +/- 0.03) x 10(-8) eV for b
= 1 mm.