Optical-optical double-resonance spectroscopy of high vibrational levels of the Na 2 A 1Σ u+ state in a molecular beam

Abstract

High vibrational bands of the Na 2 A-X system are investigated in a molecular beam by two-step excitation at separate interaction regions. With a first laser A-state levels are optically pumped; they decay radiatively and populate high vibrational levels of the ground state (e.g. υ′' = 31). A second laser excitation starting from these prepared levels allows the investigation of high vibrational levels of the A state, for example υ′ = 66, 67, 68, 69 and υ′ = 70. From analysis of the υ′ = 66, …, 70-υ′' = 31 bands we obtain B(υ) and G(υ) and, including the data of others, we determined a new RKR potential curve for the A 1Σ u + state, extending the experimentally determined potential from υ′ = 44 to υ′ = 70 (78% of the well depth).