Vibrational and rotational analysis of perturbed electronic states of borylene through optical-optical double resonance excitation
Abstract
The purpose of this research project was to investigate the effect of perturbations to two low-lying potential surfaces of borylene. A standard Wiley-McClaren time-of-flight (TOF) mass spectrometer detected mass-selected ion signals produced by resonance-enhanced multiphoton ionization (REMPI). Rovibronic transitions of the A 1Π and B 1Σ + electronic states investigated using one-colour and optical-optical double resonance spectroscopy. Transitions to the A 1Π state of BH, produced in a pulsed free jet by 193nm photolysis, were observed in the regions of 396nm, 370nm and 351nm for the (1–0), (2–0) and (3–0) vibrational bands. All rotational line positions recorded for 11 BH (1–0) and (2–0) bands are well described by the spectroscopic parameters established by Fernando and Bernath. While spectroscopic constants were previously derived for the (3–0) band, a new set is presented here. Additionally, a new experimentally derived barrier height for the A 1Π state has been determined. Five previously unobserved vibrational bands of the outer potential minimum of the B 1Σ + state are presented here. These observations offer the first experimental view of the outer potential well. The minimum has been determined to lie at lower energy than theoretical calculations have predicted. Measurements of the relative spacings for the outer vibrational levels indicate a broader potential surface than determined with ab-initio calculations. Observation of rovibrational energy levels of the outer potential energy surface of B 11Σ+ was only viable through the application of optical-optical double resonance spectroscopy.
Degree
Ph.D.
Advisors
Grant, Purdue University.
Subject Area
Physical chemistry|Chemistry
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