Observation of the double optical-gamma resonance in Mössbauer spectra of 151 Eu in EuP 5 O 14 single crystal

Abstract

A theoretical analysis has been made and calculation procedures have been developed for describing the hyperfine structure of 151Eu Mossbauer spectra and the effect of double optical-gamma resonance (DOGR) in the presence of hyperfine quadrupole interaction with an arbitrary symmetry of the electric field gradient tensor. An experimental setup was designed for DOGR-effect observation, incorporating the pumping argon laser and the tunable dye laser combined with the Mossbauer spectrometer on a common platform. The Mossbauer absorption spectra of 151Eu3 + nuclei in single crystals of europium pentaphosphate, EuP5O14, have been measured at T = 5 K and 80 K under the absence and presence of optical pumping tuned to the 7F\(_{0}-^{5}\)D0 electronic transition at the 578 nm wavelength. A simultaneous analysis of these spectra in terms of the spin Hamiltonian of hyperfine quadrupole interaction has allowed us to evaluate the DOGR-effect magnitude with the population of the excited (5D0) electronic state under optical pumping of about 10 %.