Infrared Spectrum of Fulvenallene and Fulvenallenyl in Helium Droplets.

Fulvenallene is the global minimum on the CH potential energy surface. Rearrangement of fulvenallene to other CH species and dissociation to produce fulvenallenyl radical (CH) is carried out in a continuous-wave SiC pyrolysis furnace at 1500 K. Prompt pick-up and solvation by helium droplets allows for the acquisition of vibrational spectra of these species in the CH stretching region.

Ethyl + O in Helium Nanodroplets: Infrared Spectroscopy of the Ethylperoxy Radical.

Helium-solvated ethylperoxy radicals (CHCHOO) are formed via the in situ reaction between A' ethyl radical and Σ dioxygen. The reactants are captured sequentially through the droplet pick-up technique. Helium droplets are doped with ethyl radical via pyrolysis of di- tert-amyl peroxide or n-propylnitrite in an effusive, low-pressure source.

Sequential Capture of O(P) and HCN by Helium Nanodroplets: Infrared Spectroscopy and ab Initio Computations of the Σ O-HCN Complex.

Catalytic thermal cracking of O is employed to dope helium droplets with O(P) atoms. Mass spectrometry of the doped droplet beam reveals an O dissociation efficiency larger than 60%; approximately 26% of the droplet ensemble is doped with single oxygen atoms. Sequential capture of O(P) and HCN leads to the production of a hydrogen-bound O-HCN complex in a Σ electronic state, as determined via comparisons of experimental and theoretical rovibrational Stark spectroscopy.

Infrared Stark and Zeeman spectroscopy of OH-CO: The entrance channel complex along the OH + CO → trans-HOCO reaction pathway.

Sequential capture of OH and CO by superfluid helium droplets leads exclusively to the formation of the linear, entrance-channel complex, OH-CO. This species is characterized by infrared laser Stark and Zeeman spectroscopy via measurements of the fundamental OH stretching vibration. Experimental dipole moments are in disagreement with ab initio calculations at the equilibrium geometry, indicating large-amplitude motion on the ground state potential energy surface.

Mid-infrared signatures of hydroxyl containing water clusters: Infrared laser Stark spectroscopy of OH-H2O and OH(D2O)n (n = 1-3).

Small water clusters containing a single hydroxyl radical are synthesized in liquid helium droplets. The OH-H2O and OH(D2O)n clusters (n = 1-3) are probed with infrared laser spectroscopy in the vicinity of the hydroxyl radical OH stretch vibration. Experimental band origins are qualitatively consistent with ab initio calculations of the global minimum structures; however, frequency shifts from isolated OH are significantly over-predicted by both B3LYP and MP2 methods.

Infrared Spectroscopy of OH··CH3OH: Hydrogen-Bonded Intermediate Along the Hydrogen Abstraction Reaction Path.

Substantial non-Arrhenius behavior has been previously observed in the low temperature reaction between the hydroxyl radical and methanol. This behavior can be rationalized assuming the stabilization of an association adduct in the entrance channel of the reaction, from which barrier penetration via quantum mechanical tunneling produces the CH3O radical and H2O. Helium nanodroplet isolation and a serial pick-up technique are used to stabilize the hydrogen bonded prereactive OH··CH3OH complex.