Further spectroscopic investigations of the high energy electronic states of SrOH:: The (B)over-tilde′2Σ+(000)-(A)over-tilde2Π(000) and the (D)over-tilde2Σ+(000)-(A)over-tilde2Π(000) transitions

The (B) over tilde ('2)Sigma(+) and (D) over tilde (2)Sigma(+) states of SrOH were investigated using optical-optical double-resonance (OODR) spectroscopy. Rotational and fine structure parameters have been determined for these two states through a combined least-squares fit of the current OODR data along with the OODR data of the (C) over tilde (2)pi-(A) over tilde (2)pi transition, the optical data of the (A) over tilde (2)pi-(X) over tilde (2)Sigma(+) transition and the millimeter-wave pure rotational measurements of the (X) over tilde (2)Sigma(+) state. The spin-rotation constant, gamma, of the (B) over tilde'Sigma(+) state was found to be 0.002653 cm(-1), which is two orders of magnitude smaller than that of the (B) over tilde (2)Sigma(+) state (-0.1447 cm(-1)). This small T value suggests that this state arises from a Sr+ atomic orbital of mainly 6s sigma character. This atomic orbital assignment is also supported by the large rotational constant observed in the (B) over tilde'(2)Sigma(+) state and the similarity of the molecular constants to those of the (D) over bar (2)Sigma(+) state of CaOH. The rotational energy levels of the (D) over tilde (2)Sigma(+)state of SrOH were found to be largely perturbed, which prohibited the accurate determination of the spin-rotation constant in this state. This perturbation is most likely due to an interaction with a (2)Sigma vibronic component of the nearby (C) over tilde (2)pi state. (c) 2007 Elsevier Inc. All rights reserved.