Observation of the quasibound energy levels and tunnelling lifetimes in the Na 2 B 1Π u state

Abstract

All quasibound vibrational energy levels υ′= 27–33 of the Na 2 B 1 Π u state are accessed via a triple resonance excitation scheme: cw modulated gain spectroscopy (MGS). Two independent analyses involve a Padé-type near-dissociation representation of the observed energies and non-linear least-squares fits to the lineshapes. The results are values for the barrier height (379.3 ±2.3 cm −1 above the center of gravity of the 3s + 3p separated atom limit), the total number of quasibound, rotationless energy levels (υ′max = 33), and tunnelling lifetimes for υ′= 33, J = 3–17 (τ = 93.5 ± 2.8 ps-18.3 ± 1.1 ps).