RbCs bands observation and interpretation

Abstract

We calculated the approximate form of absorption bands of RbCs molecules in the 450–1000 nm wavelength range. The manifold of potential curves for the Hund’s coupling case a was used to predict the absorption spectra assuming constant transition dipole moments, which can serve as a first approximation for the comparison with experimental results and their interpretation. Any substantial departure of an observed spectrum from the predicted one would point to the need of more complex calculations comprising transition-dipole-moment functions and spin–orbit interaction. Comparison with RbCs absorption bands from hot vapor is discussed. The band at 717 nm is identified as the 1¹Σ⁺→1¹Π transition (B–X band) and the diffuse band at 563 nm as the 1¹Σ⁺→3¹Π transition.