First Experimental Observation on Different Ionic States of both Methylthio (CH3S.) and Methoxy (CH3O.) Radicals

Zhu, Xin Jiang; Ge, Mao Fa; Wang, Jing; Sun, Zhuo; Wang, Dian Xun

doi:10.1002/1521-3757(20000602)112:11<2016::aid-ange2016>3.0.co;2-6

Cited by 19 publications

(8 citation statements)

References 39 publications

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“…The PE spectrum was recorded on a double-chamber UPS-II machine which was built specifically to detect transient species at a resolution of about 35 meV as indicated by the Ar + ( 2 P 2/3 ) photoelectron band [11] . Experimental vertical ionization energy (E v in eV) is calibrated by simultaneous addition of a small amount of argon and methyl iodide to the sample.…”

Section: Environmental Chemistrymentioning

confidence: 99%

A novel heterogeneous reaction for generating gaseous nitrous acid

Wang

Yao

et al. 2007

Chin. Sci. Bull.

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The short-lived reactive specimen nitrous acid HONO was generated in the gas phase by the heterogeneous reaction of gaseous HCl with AgNO 2 which can generate higher concentration of HONO than other methods. We investigated the process from generation to dissociation in the gas phase under different controlled temperatures, and discussed the ionization and reaction on the solid surface by combination of the photoelectron spectroscopy and photoionization mass spectroscopy (PES-PIMS) and in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS). HONO, PES-PIMS, DRIFTSOH is a key reactive species in the troposphere, playing a primary role in the formation of ozone and other secondary atmospheric pollutants [1] . Photodissociation of nitrous acid (HONO) is thought to be a significant source of OH radicals in remote and polar regions [2,3] and also in the polluted troposphere. For example, Winer and Biermann [4] reported that HONO photolysis accounted for almost all the OH produced during the first few hours after sunrise on a typical day in Long Beach, CA. In addition to being a source of OH, HONO has been shown to form nitrous oxide in surface reaction of which the mechanism is not yet well defined [5] . This is potentially significant on a global scale, since there are uncertainties in the budget of N 2 O [6] .The mechanisms of HONO formation in the atmosphere are not very clear at present. Evidence of heterogeneous HONO production through the surface reaction of NOx with water or soot was experimentally observed in smog chamber [7] and flow tube studies [8] . This kind of heterogeneous reaction is used to explain the high concentrations measured in the atmosphere.The electronic and molecular structures of molecule are related to their activity. We have a long-standing interest in the generation, spectroscopy and structure of small stable and unstable species [9,10] . Herein we present a novel method to generate nitrous acid in the gas phase, and the processes of generation and dissociation studied by photoelectron spectroscopy (PE), photoionization mass spectroscopy (PIMS) and in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) are also discussed. The measured ionization energy has been assigned with the aid of OVGF calculations.

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Section: Environmental Chemistrymentioning

confidence: 99%

A novel heterogeneous reaction for generating gaseous nitrous acid

Wang

Yao

et al. 2007

Chin. Sci. Bull.

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“…was then characterized by in situ PES, and the point of pyrolysis quartz tube is closely (1.5 cm) coupled to the ionization zone in the PES. New PE bands appeared in comparison to the recognized PE spectrum of parent reference molecule CH 3 SSCH 3 [52] .…”

Section: Rs (R = Ch 3 Ch 3 S Ch 3 Ch 2 (Ch 3 ) 2 Ch)mentioning

confidence: 91%

“…The assignments of remaining bands are listed in Table 5. [52] C s -CH 3 SS . ( 2 A″) [62] C s -CH 3 CH 2 S .…”

Section: Rs (R = Ch 3 Ch 3 S Ch 3 Ch 2 (Ch 3 ) 2 Ch)mentioning

confidence: 99%

“…Recently, we investigated the pyrolysis (double-heater inlet system at 275 ± 0.5℃) of CH 3 ONO with the catalysis of molecular sieve (4 Å), and the full PE spectrum of radical CH 3 O . , as well as transition energies for different ionic states, has been first obtained (Table 4) [52] .…”

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confidence: 99%

“…The removal of an electron from the HOMO will produce the CH 3 O + cation in the 3 A 2 , 1 E, Table 4 Experimental vertical ionization energies IP (eV) for transitions from ground states to different ionic states of alkoxy radicals RO . (R = CH 3 , [52] C s -CH 3 CH 2 O . ( 2 A″) [53] C s -(CH 3 ) 2 CHO .…”

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Novel gaseous transient species: Generation and characterization

Zeng

Wang

2007

SCI CHINA SER B

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Due to special properties of transient species, such as short-lived, unstable, reactive, and even explosive, the generation and subsequent characterization is a great challenge for experimental chemists. In our laboratory, systematic researches have been carried out to investigate novel transient species: reactive halogen species (RHS), short-lived free radicals, and metastable pseudohalogen compounds, based on the successive technical improvements on the HeI Photoelectron spectroscopy (PES). In this review, the topic mainly focuses on innovative methods of generating novel transient species, and subsequent geometric and electronic structure characterizations of these species combined with quantum chemical calculations.reactive halogen species, radicals, pseudohalogen compounds, HeI Photoelectron Spectroscopy (PES), quantum chemical calculations

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The CH3N Diradical: Experimental and Theoretical Determinations of the Ionization Energies

et al. 2001

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Methylnitrene, the CH 3 N diradical, is one of the most interesting of all organic free radicals, and it has drawn a lot of attention in both experiments [1±5] and theory. [6±11] As the simplest alkyl nitrene, the general class of molecules with the form RN, CH 3 N is a dielectronic radical similar to carbene CH 2 : , and is thought to be an important intermediate in many organic and inorganic reactions. [12±14] Berry suggests [1] that the alkyl nitrene should have electron states similar to NH which has been well characterized by spectroscopists. However, much less is known about alkyl nitrenes such as CH 3 N, CH 3 CH 2 ÀN, (CH 3 ) 2 CHÀN, or (CH 3 ) 3 CÀN. There are no reports on the ionization energy of the nitrenes until now, but these ionization energies, especially the first ionization energy, are important physical and chemical data.When combined with ab initio molecular orbital calculations, HeI photoelectron spectroscopy (PES) gives a lot of information on the electronic and vibrational structures, the configuration, the bonding characteristics, as well as the relative photoionization cross sections of different molecular orbitals. Of course, the most important information obtained from the PES study is the ionization energy of the different molecular orbitals. Pople [15] and Ng [16] and their co-workers pointed out that the ab initio Gaussian 2 (G2) calculation can correctly predict the first ionization energy.We have shown how to generate a continuous flowing beam of short-lived species by the microwave discharge or pyrolysis of the parent species, allowing us to perform PES studies on reactive open-shell species such as NO 3 , [17] (CH 3 ) 2 N, [18] CH 3 O, [19] CH 3 S, [19] CH 3 SS, [20] CH 3 CH 2 S, [21] (CH 3 ) 3 CO [22] and further demonstrated that the G2 calculation can also predict the ionization energies of different ionic states. Herein, we present the experimental and theoretical determinations of the ionization energies of different ionic states for the CH 3 N diradical; this is also the first report on ionization energy for the nitrenes.Calculations on the CH 3 N 3 molecule indicate that the bond between the CH 3 N and N 2 units is the weakest present and therefore pyrolysis of the CH 3 N 3 offers a simple route to the CH 3 N diradical through loss of the N 2 unit. [23±26] However, in the pyrolysis study of CH 3 N 3 carried out by Bock and coworkers, [24±26] no PES signals of the CH 3 N diradical could be detected and PES signals attributed to CH 2 NH appeared when CH 3 N 3 was heated to 770 K.Through careful analysis of the experimental process used by Bock et al. [24±26] it is clear that: 1) the distance from the point of pyrolyzation of the parent compound to the photoionized point for the new species generated is too far (maybe more than half meter); 2) the pyrolysis temperature (770 K) for maintaining the new species is also too high. Obviously, it is difficulty to record the PES signals of transient species which have a short life-time, such as the CH 3 N diradical. I...

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First Experimental Observation on Different Ionic States of both Methylthio (CH3S.) and Methoxy (CH3O.) Radicals

Cited by 19 publications

References 39 publications

A novel heterogeneous reaction for generating gaseous nitrous acid

A novel heterogeneous reaction for generating gaseous nitrous acid

Novel gaseous transient species: Generation and characterization

The CH3N Diradical: Experimental and Theoretical Determinations of the Ionization Energies

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