Structure of the R1 and R2 Bands of Isotopes of Cr3+ Ion in a Single Crystal of Ruby at Room Temperature

Room-temperature absorption and luminescence spectra of the R 1 and R 2 bands in a single crystal of Ruby Al 2 O 3 :Cr 3+ (0.05%) are analyzed. The luminescence in these bands was induced both by crystal excitation by radiation of a halogen lamp and by selective excitation of two upper levels of the 2 T 1 state by radiation of a tunable laser diode (656–662 nm). Four different shifts of the R 1 and R 2 bands and four different distances between these bands the change in which is a multiple of ~0.52 cm –1 are discovered in spectra of se-lectively excited luminescence bands. Detailed comparative analysis of the obtained spectral bands of luminescence and corresponding absorption spectra allowed determining combined structure of each of the R 1 and R 2 bands formed by satellite doublets of these bands associated with all four stable isotopes 50 Cr 3+ , 52 Cr 3+ , 53 Cr 3+ , and 54 Cr 3– of chromium ions. Splitting of these doublets varies from 7.04 to 9.14 сm –1 depending on the isotope mass.