Time dependence of a level anticrossing signal in exciton emission from a GaSe crystal under resonant excitation conditions

The time dependence of the Zeeman-sublevel anticrossing signal in triplet-bound exciton emission from gallium selenide has been investigated under resonant excitation conditions. It has been found that the shape of the anticrossing signal varies during the lifetime of the excited state. The time dependence of the anticrossing signal in the case of the resonant excitation of exciton states differs significantly from the corresponding dependence observed in the case of the band-to-band excitation of luminescence. A theoretical description is proposed for the observed effects.