A mini-TOF photofragment translational spectrometer – photofragmentation of CF3I at 281.73 nm

Tian, Zhixin; Bi, Weibin; Deng, Helen; Wang, Xu; Tang, Zichao; Zhu, Qihe

doi:10.1016/j.cplett.2004.10.071

Cited by 15 publications

(6 citation statements)

References 11 publications

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“…The PTS experiment of the C 2 H 5 I photofragmentation was performed in our new mini-TOF photofragment translational spectrometer [20] . Its structure is shown in the diagram (Figure 1).…”

Section: Methodsmentioning

confidence: 99%

High-resolution photofragment translational spectroscopy for the UV photodissociation of C2H5I

Huang

et al. 2007

SCI CHINA SER B

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The photodissociation of ethyl iodide at 279.71, 281.73, 304.02 and 304.67 nm has been studied on our new mini-photofragment translational spectrometer with a total flight path of only 5 cm. Some vibrational peaks are firstly resolved in the TOF spectra of I*( 2 P 1/2 ) and I( 2 P 3/2 ) channels. These vibrational peaks are assigned to the excitation states (ν 2 = 0, 1, 2,…) of the umbrella mode (ν 2 , 540 cm −1 ) of the photofragment C 2 H 5 , and the distribution of the vibrational states is obtained. The dissociation energy has been determined to be D 0 (C-I)=2.314 ± 0.03 eV. The energy partitioning of the available energy (E avl =E T +E int =E T +E V,R ) calculated from our experimental data / int avl E E = 22.1% at 281.73 nm, 22.4% at 304.02 nm for the I* channel, and / int avl E E = 25.2% at 279.71 nm, 25.9% at 304.67 nm for the I channel, seem to be more reliable. photofragment translational spectroscopy, C 2 H 5 I, photodissociation, vibrational state distribution, energy partitioning，dissociation energyFor the photodissociation of molecules, photofragment translational spectroscopy offers a way to study the dynamics of photodissociation in a collision-free regime [1] . Analysis of the velocity distribution and the angular distribution of the photofragments can give information of the potential energy surfaces, the energy partitioning, the vibrational state distribution of the photofragments, the dissociation energy, the life time of the excitation state and the curve-crossing. The original photofragment translational spectrometer (PTS) [2,3] was with the structure that the molecular beam, the laser, and the detection axis were perpendicular to each other. The improved PTS, with the molecular beam rotatable, was called the "Rotating Source Machine" at Yuan Lee's Lab in U.C. Berkeley [4] . At the same time, similar experimental set-ups were built in the University of Manchester [5] and in our laboratory [6,7] . This kind of experimental apparatus is still used in many laboratories. Some high resolution experimental results have been obtained [8,9] , but the apparatus is very complicated and in need of ultra-high vacuum up to 10 −8 Pa. At present, the ion imaging apparatus, originally designed by Chandler and Houston [10] , and improved by Eppink and Parker [11] , is used more often. From the ion image, the angular distribution of the photofragments can be obtained simultaneously with the high-resolution velocity distribution, but high-grade uniform Micro Channel Plates (MCP) and CCD camera are required. We have built a simple and small photofragment translational spectrometer of only 5 cm total flight path and used a simple MCP as the detector. However, the resolution of this PTS is high enough to resolve some vibrational states of the photofragments.Alkyl halides have been concerned to the atmospheric chemistry due to their role in ozone depletion. The photodissociation of ethyl iodide (C 2 H 5 I) has been widely studied [12][13][14][15][16][17][18][19] . The absorption cross-section of C 2 H 5 I was meas...

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“…The PTS experiment of the C 2 H 5 I photofragmentation was performed in our new mini-TOF photofragment translational spectrometer [20] . Its structure is shown in the diagram (Figure 1).…”

Section: Methodsmentioning

confidence: 99%

High-resolution photofragment translational spectroscopy for the UV photodissociation of C2H5I

Huang

et al. 2007

SCI CHINA SER B

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“…In the I* channel, the distribution was peaking around v 1 = 6, higher than their theoretical result of peaking at v 1 = 4 or 5. Many groups have performed on the CF 3 I photodissociation at different wavelengths. − ,− For the high resolution experiments with vibrational peaks resolved, Felder and Wang et al studied the photodissociation of CF 3 I at 248 nm, and got the 701 cm –1 (ν 1 ) states resolved TOF spectrum in the I* channel with the highest peak at v 1 = 4 and 5, respectively. With the velocity map ion imaging technique, Pratt’s group got 701 cm –1 (ν 1 ) state resolved images on the CF 3 I photodissociation between 304 and 277 nm and also at 266 nm .…”

Section: Introductionmentioning

confidence: 99%

Resolved (v₁, v₂ = 1) Combination Vibrational States of CF₃ Fragments in the Photofragment Translational Spectra of CF₃I

Lin

Liu

et al. 2016

J. Phys. Chem. A

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The photodissociation of CFI → CF(v,v) + I*/I has been investigated at 248, 266, and 277 nm with our high resolution mini-TOF photofragment translational spectrometer. Based on the theoretical calculations of Clary and of Bowman et al., now in this manuscript, we assign 701 cm to the CF symmetric stretch (breathing) ν mode, and 1086 cm to the umbrella ν mode of the CF fragment. In the obtained TOF spectra of I from the I* channel, situated in the 701 cm gaps between the original series of (v, 0) vibrational peaks, a new series of weaker (v, 1) vibrational peaks are partially resolved. These observed new peaks with 1086 cm ν mode excitation have never been reported in previous literature. In the TOF spectra of I from the I channel, the new series of (v, 1) peaks are also partially resolved. However, these spectra of I channel are less satisfactory, because for higher E and higher E, the higher resolution of PTS is required. The potential energy at the curve crossing point and the excitation of CF (v, 2) and (v, 3) vibrational states have been also analyzed.

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“…The synchronization of the YAG laser with the pulsed valve was controlled by a pulse-delay generator (DG535, Stanford Research System). The frequency of the UV laser was calibrated with the REMPI frequencies of I ( 2 P 3/2 ) and I* ( 2 P 1/2 ) of methyl iodide, 28 the deviation of the frequency calibration was below 0.15 cm À1 . In the 2C-R2PI experiment, the spatial widths of the excitation and ionization UV laser beams were held at about 1 mm and 3 mm in the interaction zone, respectively.…”

Section: Experimental and Computational Methodsmentioning

confidence: 99%

Theoretical and REMPI spectroscopic study on phenylhydrazine and phenylhydrazine–(Ar)n (n = 1, 2) van der Waals complexes

Xiao

et al. 2009

Phys. Chem. Chem. Phys.

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Phenylhydrazine and its van der Waals complexes with one or two argon atoms were investigated with theoretical calculations and resonant two photon ionization (R2PI) spectroscopy. The ab initio and DFT calculations found a conversion of the orbital hybridization of the Nbeta atom from sp3-like in the S0 state to sp2-like in the S1 state, suggesting that the lone pair electrons of the Nbeta atom are involved in a super p-p-pi conjugation over the skeleton of phenylhydrazine in the S1 state. The structural change of the hydrazino group in the S1<--S0 electronic transition was reflected by the vibrational excitations of the hydrazino group observed in the 1C-R2PI spectrum. The band origin of the S1<--S0 transition is determined to be 33610 cm(-1) and the adiabatic ionization energy (IE) of phenylhydrazine, measured by 2C-R2PI spectroscopy, is 62829+/-15 cm(-1). The S1<--S0 electronic transitions of phenylhydrazine-Ar and phenylhydrazine-Ar2 complexes were also observed in the 1C-R2PI spectrum, and their band origins are, respectively, red-shifted by 39 and 80 cm(-1) from that of phenylhydrazine.

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A mini-TOF photofragment translational spectrometer – photofragmentation of CF3I at 281.73 nm

Cited by 15 publications

References 11 publications

High-resolution photofragment translational spectroscopy for the UV photodissociation of C2H5I

High-resolution photofragment translational spectroscopy for the UV photodissociation of C2H5I

Resolved (v₁, v₂ = 1) Combination Vibrational States of CF₃ Fragments in the Photofragment Translational Spectra of CF₃I

Theoretical and REMPI spectroscopic study on phenylhydrazine and phenylhydrazine–(Ar)n (n = 1, 2) van der Waals complexes

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A mini-TOF photofragment translational spectrometer – photofragmentation of CF3I at 281.73 nm

Cited by 15 publications

References 11 publications

High-resolution photofragment translational spectroscopy for the UV photodissociation of C2H5I

High-resolution photofragment translational spectroscopy for the UV photodissociation of C2H5I

Resolved (v1, v2 = 1) Combination Vibrational States of CF3 Fragments in the Photofragment Translational Spectra of CF3I

Theoretical and REMPI spectroscopic study on phenylhydrazine and phenylhydrazine–(Ar)n (n = 1, 2) van der Waals complexes

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Resolved (v₁, v₂ = 1) Combination Vibrational States of CF₃ Fragments in the Photofragment Translational Spectra of CF₃I