This talk will present results of a gas phase, jet-cooled vibronic spectroscopy study of phenylvi... more This talk will present results of a gas phase, jet-cooled vibronic spectroscopy study of phenylvinylnitrile (C6H5-CH=CH-CN, PVN). This molecule is seen as a potential photochemical precursor to nitrogen heteroaromatics, and therefore is particularly relevant to Titan's atmosphere, where nitriles exist in significant abundance. As a first step towards such photochemical studies, a fluorescence excitation spectrum of PVN spanning the range 33,500-35,840 cm −1 (298.5-279.0 nm) has been recorded, and dispersed fluorescence spectra that uncover and characterize the vibronic activity have been acquired. The S0-S1 origin is a prominent band located at 33,826 cm −1 , and the excitation spectrum is characterized by significant vibronic activity leading to spectral congestion. Hole-burning in the region of 33,500-35,840 cm −1 has also been completed, and the excitation spectrum can be assigned solely to (E)-PVN. As PVN is the nitrogencontaining counterpart to phenylvinylacetylene (PVA), a comparison of the vibronic spectroscopy between the two molecules will be made.
Resonance stabilized radicals (RSRs) are thought to be key intermediates in the formation of larg... more Resonance stabilized radicals (RSRs) are thought to be key intermediates in the formation of larger molecules in planetary atmospheres. Given the nitrogen-rich atmosphere of Titan, and the prevalence of nitriles there, it is likely that nitrile and isonitrile RSRs could be especially important in pathways leading to the formation of more complex nitrogen-containing compounds and the aerosols ("tholins") that are ultimately produced. In this talk, the results of a gas phase, jet-cooled vibronic spectroscopy study of the phenylcyanomethyl radical (C_6H_5.{C}HCN), the nitrogen-containing analog of the 1-phenylpropargyl radical, will be presented. A resonant two color photon ionization spectrum over the range 21,350-22,200 Cm-1 (450.0-468.0 nm) has been recorded, and the D_0-D_1 origin band has been tentatively identified at 21,400 Cm-1. Studies identifying the ionization threshold, and characterizing the vibronic structure will also be presented. An analogous study of the phe...
In the context of combustion, both the formation and destruction of fused-ring aromatics are impo... more In the context of combustion, both the formation and destruction of fused-ring aromatics are important to understand in some detail. Determining the principal pathways from benzene to naphthalene and on to larger polyaromatic hydrocarbons is imperative, but with increased chemical complexity is likely to involve free radicals as intermediates which are themselves structurally complex, necessitating more detailed spectroscopic characterization for their identification. Our group has recently studied the vibronic spectroscopy of a series of C10H9 and C10H11 hydronaphthyl radicals, in which their thermochemical properties were evaluated with isomer specificity. Here, we extend this characterization to include infrared spectra in the alkyl CH stretch region, and explore the spectroscopic consequences of electronic excitation on these CH stretch absorptions. Utilizing resonant ion-dip infrared spectroscopy (RIDIRS), we report the infrared spectra of 2,3,4-Trihydronaphthyl (C10H11) and In...
Titan, the sixth moon of Saturn, is regarded as a model system for studies of primordial Earth du... more Titan, the sixth moon of Saturn, is regarded as a model system for studies of primordial Earth due to a similar atmosphere (>95% N2), and the presence of a methane cycle comparable to the water cycle on Earth. The organic chemistry in Titan's atmosphere occurs via ion, radical, and neutral pathways. To date, studies have been conducted that account for the reactions that lead to the formation of benzene (78 amu). Data from the Cassini Mission verifies the presence of compounds at 78 amu and greater, suggesting the presence of benzene and possibly benzene-based derivatives. The presence of nitrogenous species such as HC3N, C2N2, and NH3 opens up the possibility of nitrogen containing benzene derivatives. Among the nitrogen-containing molecules of interest are isocyanides (also called isonitriles) which the R-NC group. The spectroscopy and photochemistry of isonitriles is less well understood than the nitrile counterparts, especially when bonded to aromatic rings. One of the is...
This talk will present results of a gas phase, jet-cooled vibronic spectroscopy study of phenylvi... more This talk will present results of a gas phase, jet-cooled vibronic spectroscopy study of phenylvinylnitrile (C6H5-CH=CH-CN, PVN). This molecule is seen as a potential photochemical precursor to nitrogen heteroaromatics, and therefore is particularly relevant to Titan's atmosphere, where nitriles exist in significant abundance. As a first step towards such photochemical studies, a fluorescence excitation spectrum of PVN spanning the range 33,500-35,840 cm −1 (298.5-279.0 nm) has been recorded, and dispersed fluorescence spectra that uncover and characterize the vibronic activity have been acquired. The S0-S1 origin is a prominent band located at 33,826 cm −1 , and the excitation spectrum is characterized by significant vibronic activity leading to spectral congestion. Hole-burning in the region of 33,500-35,840 cm −1 has also been completed, and the excitation spectrum can be assigned solely to (E)-PVN. As PVN is the nitrogencontaining counterpart to phenylvinylacetylene (PVA), a comparison of the vibronic spectroscopy between the two molecules will be made.
Resonance stabilized radicals (RSRs) are thought to be key intermediates in the formation of larg... more Resonance stabilized radicals (RSRs) are thought to be key intermediates in the formation of larger molecules in planetary atmospheres. Given the nitrogen-rich atmosphere of Titan, and the prevalence of nitriles there, it is likely that nitrile and isonitrile RSRs could be especially important in pathways leading to the formation of more complex nitrogen-containing compounds and the aerosols ("tholins") that are ultimately produced. In this talk, the results of a gas phase, jet-cooled vibronic spectroscopy study of the phenylcyanomethyl radical (C_6H_5.{C}HCN), the nitrogen-containing analog of the 1-phenylpropargyl radical, will be presented. A resonant two color photon ionization spectrum over the range 21,350-22,200 Cm-1 (450.0-468.0 nm) has been recorded, and the D_0-D_1 origin band has been tentatively identified at 21,400 Cm-1. Studies identifying the ionization threshold, and characterizing the vibronic structure will also be presented. An analogous study of the phe...
In the context of combustion, both the formation and destruction of fused-ring aromatics are impo... more In the context of combustion, both the formation and destruction of fused-ring aromatics are important to understand in some detail. Determining the principal pathways from benzene to naphthalene and on to larger polyaromatic hydrocarbons is imperative, but with increased chemical complexity is likely to involve free radicals as intermediates which are themselves structurally complex, necessitating more detailed spectroscopic characterization for their identification. Our group has recently studied the vibronic spectroscopy of a series of C10H9 and C10H11 hydronaphthyl radicals, in which their thermochemical properties were evaluated with isomer specificity. Here, we extend this characterization to include infrared spectra in the alkyl CH stretch region, and explore the spectroscopic consequences of electronic excitation on these CH stretch absorptions. Utilizing resonant ion-dip infrared spectroscopy (RIDIRS), we report the infrared spectra of 2,3,4-Trihydronaphthyl (C10H11) and In...
Titan, the sixth moon of Saturn, is regarded as a model system for studies of primordial Earth du... more Titan, the sixth moon of Saturn, is regarded as a model system for studies of primordial Earth due to a similar atmosphere (>95% N2), and the presence of a methane cycle comparable to the water cycle on Earth. The organic chemistry in Titan's atmosphere occurs via ion, radical, and neutral pathways. To date, studies have been conducted that account for the reactions that lead to the formation of benzene (78 amu). Data from the Cassini Mission verifies the presence of compounds at 78 amu and greater, suggesting the presence of benzene and possibly benzene-based derivatives. The presence of nitrogenous species such as HC3N, C2N2, and NH3 opens up the possibility of nitrogen containing benzene derivatives. Among the nitrogen-containing molecules of interest are isocyanides (also called isonitriles) which the R-NC group. The spectroscopy and photochemistry of isonitriles is less well understood than the nitrile counterparts, especially when bonded to aromatic rings. One of the is...
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