title: The Near-Infrared (3)Phi --> (1)(3)Delta Transition of LaF.
abstract: Rotational analyses of 32 subbands of the near-infrared (3)Phi --> (1)(3)Delta system of LaF have been carried out, involving the levels v = 0-7 of the two states. The three subsystems were first treated as separate singlet systems, directly at equilibrium. Perturbations were revealed in the lower state, ascribed to spin-uncoupling interactions between (1)(3)Delta(3)(v) and (1)(3)Delta(2)(v + 1) levels. A 21 x 21 matrix representation at equilibrium of the complex of interacting levels (v = 0-6) was then constructed, each diagonal v-block corresponding to a triplet model of the rovibrational (3)Delta Hamiltonian. The observed perturbations were completely reduced in the harmonic oscillator approximation with an experimental value of the interaction parameter B(Delta)(0,1) = 0.01322(2) cm(-1). The wavenumbers of some 4500 lines of the system were fitted with an rms error of about 0.005 cm(-1). (Line lists are available in electronic form via http://www-obs.univ-lyon1.fr/~ABernard/index.html.) Copyright 2000 Academic Press.
authors.affiliation: CRAL-Observatoire Astronomique de Lyon, Saint-Genis-Laval Cedex, 69561, France
authors.initials: A
authors.lastname: Bernard
authors.initials: C
authors.lastname: Effantin
authors.initials: J
authors.lastname: d'Incan
authors.initials: J
authors.lastname: Vergès