Isotope Shifts of Zero-Phonon Transition in Highly Purified NaNO₂ Crystal

Abstract

Low temperature optical spectra of highly purified NaNO₂ crystals have been investigated in near uv region. The width of the zero-phonon absorption line at ν₀₀ due to the electronic transition ¹A₁→¹B₁ in NO₂⁻ is remarkably reduced in the purified crystal and three satellite absorption lines are observed separately from the high energy tail of the strong zero-phonon absorption line. The energy separations of these lines from ν₀₀ are 4±1, 6±1 and 7.5±1 cm⁻¹ and are identified as the isotope shifts of the zero-phonon transition in NO¹⁷O⁻, NO¹⁸O⁻ and ¹⁵NO₂⁻, respectively.