Optical–optical double resonance (OODR) studies of the halogen ion-pair states. Part 2.—The f(0 +g)→ B(0 +u) transition dipole moment function in I2

Abstract

The electronic transition dipole moment function, µ_{f → B}(R), for I₂ has been determined over the range 3–5 Å by simulation of the dispersed fluorescence from a range of upper vibrational levels of the f(0⁺_g) ion-pair state. µ_{f → B}(R) displays a maximum close to R_e of the upper state. The decrease in transition dipole at R < R_e is discussed in terms of the changing electronic structure of the ion-pair state. The lifetime of the f(v′= 0) state has also been measured (τ= 13.6 ± 0.7 ns), together with the ratio of fluorescent intensities from f(v′= 0) to the B″, A and B states, enabling the f → B transition dipole function to be determined absolutely from this calibration at R_e, where µ_{f → B}= 3.0 D (1 D = 3.335 64 × 10^–30 C m).