THE (A)OVER-TILDE(2)A(1)-(X)OVER-TILDE(2)B(1) TRANSITION OF H2O-INFRARED REGION( IN THE NEAR)

A titanium sapphire laser spectrometer along with velocity modulation detection was used to record, between 12000 and 13400cm(-1), the absor ption spectrum of the (A) over tilde(2)A(1)-(X) over tilde(2)B(1) elec tronic transition of H2O+ produced in an ac glow discharge with a gas mixture of He/H2O. The Sigma(0,7,0)-(0,0,0) transition has been observ ed at 13411cm(-1) and revised rotational assignments are presented. Th e Delta(0,7,0)-(0,0,0) and Pi(0,6,0)-(0,0,0) transitions have been obs erved for the first time, at 13331 and 12494 cm(-1), respectively. The vibrational assignment follows the vibrational numbering of Brommer c t al. [J. Chem. Phys. 98, 5222 (1993)]. The rotational analysis was pe rformed using the combination differences technique. Strong perturbati ons are observed, they are tentatively explained in term of rovibronic interactions. A set of effective molecular parameters has been obtain ed for each vibrational level of the A state. The values of the spin-o rbit parameter are reported, they illustrate the vibronic coupling bet ween the two electronic states. (C) 1997 American Institute of Physics .