High-resolution photofragment translational spectra of the photodissociation of CF3I at 248 nm

Wang, Xu; Tian, Zhixin; Shi, Tujin; Shi, Xinghua; Yang, Dan; Zhu, Qihe

doi:10.1016/j.cplett.2003.07.027

Cited by 13 publications

(17 citation statements)

References 17 publications

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“…These fine peaks are very important and are enlarged as shown in Figure a. The profile of the broad peak A is quite similar to the TOF spectra in the papers of Felder and Wang et al However, now, between the original series of (v 1 , 0) stronger fine peaks, there are a new series of weaker fine peaks partially resolved.…”

Section: Resultssupporting

confidence: 72%

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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Section: Resultssupporting

confidence: 72%

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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“…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.…”

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confidence: 97%

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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“…1. Note that the 3 Q 0 À curve is omitted in the diagram since transition to this state from X ˜A1 is forbidden and, as can be concluded from the vibrational state distributions in the CF 3 fragments, [42][43][44] its influence on the dissociation dynamics also is negligible. The PES data have been obtained at the minimal energy path geometry for the ground state, i.e., the ground state energy has been optimized by varying the F-C-F umbrella angle a for every C-I distance.…”

Section: Resultsmentioning

confidence: 99%

“…The dissociation energy (D e ) of the ground state can be estimated from the average energy of the five O states (A 1 , A 2 , 3E) converging to the lowest CF 3 + I( 2 P 3/2 ) dissociation limit at 42 18 700 cm À1 , 43 18 754 AE 175 cm À1 , 44 18 780 AE 105 cm À1 . 48 It can be seen that the ground state bond strength is somewhat overestimated in the present study.…”

Section: Bothmentioning

confidence: 99%

Potential energy surfaces for ground and excited electronic states of the CF3I molecule and their relevance to its A-band photodissociation

Alekseyev

Liebermann

Buenker

2013

Phys. Chem. Chem. Phys.

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The multireference spin-orbit (SO) configuration interaction (CI) method in its Λ-S contracted SO-CI version is employed to calculate two-dimensional potential energy surfaces for the ground and low-lying excited states of CF3I relevant to its photodissociation in the lowest absorption band (A band). The computed equilibrium geometry for the X̃A1 ground state and vibrational frequency ν3 for the C-I stretch mode agree well with available experimental data. The (3)Q0(+) state dissociating to the excited I((2)P1/2) limit is found to have a minimum of 1570 cm(-1) significantly shifted to larger internuclear distances (RC-I = 5.3 a0) relative to the ground state. Similar to the CH3I case, this makes a single-exponent approximation commonly employed for analysis of the CF3I recoil dynamics unsuitable. The 4E((3)A1) state possessing an allowed transition from the ground state and converging to the same atomic limit as (3)Q0(+) is calculated to lie too high in the Franck-Condon region to have any significant impact on the A-band absorption. The computed vertical excitation energies for the (3)Q1, (3)Q0(+), and (1)Q states indicate that the A-band spectrum must lie approximately between 31,300 and 45,200 cm(-1), i.e., between 220 and 320 nm. This result is in very good agreement with the measured absorption spectrum.

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High-resolution photofragment translational spectra of the photodissociation of CF3I at 248 nm

Cited by 13 publications

References 17 publications

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

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

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

Potential energy surfaces for ground and excited electronic states of the CF3I molecule and their relevance to its A-band photodissociation

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High-resolution photofragment translational spectra of the photodissociation of CF3I at 248 nm

Cited by 13 publications

References 17 publications

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

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

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

Potential energy surfaces for ground and excited electronic states of the CF3I molecule and their relevance to its A-band photodissociation

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

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