Alpha decay of the first excited state of the Th-229 nucleus

The α decay of the anomalously low-lying isomeric level 3/2 + (3.5±1.0 eV) of the 229 Th nucleus is studied. The lifetime of the isomer with respect to a decay is predicted and the spectrum of the emitted a particles is calculated. It is noted that the complete α spectrum of the isomer and accelerated α decay of 229 Th can be observed by exciting the nuclei with laser radiation.