Spectroscopic investigation of vibrational coupling in formyl radicals and ions
Abstract
This work represents a combined study of the different vibronic couplings in the formyl and deuterated formyl radicals and ions, including Fermi resonance and Renner-Teller coupling. These studies involve the investigation of gas-phase, rovibrationally cooled HCO and DCO using several multi-laser techniques. Vibrational levels in three electronic states were explored, the 3p2Π Rydberg state and the Ã2A″ excited state of HCO/DCO radicals, and the 1Σ + ground electronic state of HCO+/DCO+. The examination of the 3p2Π Rydberg state utilized a sensitive two-laser technique called assisted resonant enhance multiphoton ionization (REMPI) spectroscopy. Coupling this method with a comprehensive simulation of the observed vibronic levels yielded a precise determination of the spectroscopic constants for the 3p2Π state. Also using assisted REMPI spectroscopy, we experimentally measured the ν3 fundamental for HCO, the assignment of which was confirmed by double resonant autoionization spectroscopy. This study shows the effects of the Renner-Teller coupling and a possible Fermi resonance in (040) DCO. In the Ã2A ″ electronic state vibronic coupling produces dissociative vibrational levels when ν2 is excited to a level with an even quantum number. By using resonant ion dip spectroscopy, we were able to measure the rotational lifetime of both the short lived dissociative even vibrational level (0 12 0) and of the longer lived odd vibrational levels of (0 11 0) and (0 13 0). Finally, by exploring the higher vibrational levels of 1Σ + DCO+, we have observed a Fermi resonance between the (1000) and (0400) vibrational levels for the first time.
Degree
Ph.D.
Advisors
Grant, Purdue University.
Subject Area
Chemistry
Off-Campus Purdue Users:
To access this dissertation, please log in to our
proxy server.