Further spectroscopic investigations of the high energy electronic states of SrOH: The B∼′2Σ+(000)–A∼2Π(000) and the D∼2Σ+(000)–A∼2Π(000) transitions

Abstract: The and 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 transition, the optical data of the transition and the millimeter-wave pure rotational measurements of the state. The spin–rotation constant, γ, of the state was found to be 0.002653cm−1, which is two orders of magnitude smaller than that of the state (−0.1447cm−1). This small γ value suggests that this state arises from a Sr+ atomic orbital of mainly 6sσ character. This atomic orbital assignment is also supported by the large rotational constant observed in the state and the similarity of the molecular constants to those of the state of CaOH. The rotational energy levels of the 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 2Σ vibronic component of the nearby state. [Copyright &y& Elsevier]