Two-photon laser generation of exciton states in krypton cryocrystals as a method for excitation of an anomalous low-energy isomeric nuclear state in the Thorium-229 isotope, Borisyuk P.V., Myzin D.A., Gubskiy K.L., Didenko N.V., Korneev P.A., Kuznetsov A.P., Lebedinskii Yu.Yu., Nauryzbaev Ja.M., Popruzhenko S.V., Chubunova E.V., Shilov V.A., Tkalya E.V.
Borisyuk et al. (Mon,) studied this question.