Product angular anisotropy in CO2 photodissociation at 157 nm

Lu, I‐Chung; Lin, Jim J.; Lee, Shi-Huang; Lee, Yuan T.; Yang, Xueming

doi:10.1016/j.cplett.2003.07.035

Cited by 23 publications

(24 citation statements)

References 9 publications

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“…More recently laser or synchrotron based techniques such as REMPI or VUV Ionization have been used to monitor production of specific fragments [e.g. Kimmel and Orlando (1995), Lu et al (2003)]. In the case of O(1S) LeClair and McConkey (1993) solved the problems of both sensitivity and selectivity by using a solid Xe surface at 65K as the basic detector element.…”

Section: Introductionmentioning

confidence: 99%

Metastable oxygen atom detection using rare gas matrices

Kedzierski¹,

Blejdea²,

DiCarlo³

et al. 2010

J. Phys. B: At. Mol. Opt. Phys.

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Abstract:The use of solid rare gas matrices as detectors of metastable oxygen atoms is investigated. A 100 eV electron beam colliding with N2O target gas is used as the source of O( 1 S). Parameters considered are surface temperature, time delay of excimer emission and spectral response to O( 1 S). In all cases detector sensitivity maximised at temperatures ≤20K. Krypton was found to provide the most sensitive surface and Ne the least.

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Section: Introductionmentioning

confidence: 99%

Metastable oxygen atom detection using rare gas matrices

Kedzierski¹,

Blejdea²,

DiCarlo³

et al. 2010

J. Phys. B: At. Mol. Opt. Phys.

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“…Previous studies of cold CO 2 photodissociation at 157 nm (63 690 cm 1 ) showed that the fragments' angular distributions associated with channel (I) are anisotropic ( β = 1.25), as expected for fast dissociation involving initial excitation via a parallel transition to the 1 B 2 state. 17,85 In contrast, the angular distributions of CO fragments produced via channel (II) at the same wavelength are nearly isotropic, 21 with β decreasing strongly with decreasing kinetic energy and CO rovibrational excitation, even though the initially excited state is short lived. 17 It was proposed that the initially excited state may have crossed to a predissociative state whose lifetime is longer than the rotational period of CO 2 .…”

Section: Implications To Co 2 Photodissociation Dynamicsmentioning

confidence: 99%

“…In contrast to the many studies of the VUV photodissociation of CO 2 , [12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27] where absorption cross sections from the a) Current address: Center for Free-Electron Laser Science, DESY, Notkestrasse 85, 22607 Hamburg, Germany. b) Email: reisler@usc.edu ground vibrational state are large, very little is known about the photodissociation at energies closer to the lowest dissociation threshold to O( 3 P) + CO(X 1 Σ + ), which is just above the band origins of the lowest excited singlet states, A 1 B 2 and B 1 A 2 .…”

Section: Introductionmentioning

confidence: 99%

Temperature dependence of the photodissociation of CO2 from high vibrational levels: 205-230 nm imaging studies of CO(X1Σ+) and O(3P, 1D) products

Sutradhar

Samanta

et al. 2017

The Journal of Chemical Physics

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The 205-230 nm photodissociation of vibrationally excited CO at temperatures up to 1800 K was studied using Resonance Enhanced Multiphoton Ionization (REMPI) and time-sliced Velocity Map Imaging (VMI). CO molecules seeded in He were heated in an SiC tube attached to a pulsed valve and supersonically expanded to create a molecular beam of rotationally cooled but vibrationally hot CO. Photodissociation was observed from vibrationally excited CO with internal energies up to about 20 000 cm, and CO(XΣ), O(P), and O(D) products were detected by REMPI. The large enhancement in the absorption cross section with increasing CO vibrational excitation made this investigation feasible. The internal energies of heated CO molecules that absorbed 230 nm radiation were estimated from the kinetic energy release (KER) distributions of CO(XΣ) products in v″ = 0. At 230 nm, CO needs to have at least 4000 cm of rovibrational energy to absorb the UV radiation and produce CO(XΣ) + O(P). CO internal energies in excess of 16 000 cm were confirmed by observing O(D) products. It is likely that initial absorption from levels with high bending excitation accesses both the AB and BA states, explaining the nearly isotropic angular distributions of the products. CO(XΣ) product internal energies were estimated from REMPI spectroscopy, and the KER distributions of the CO(XΣ), O(P), and O(D) products were obtained by VMI. The CO product internal energy distributions change with increasing CO temperature, suggesting that more than one dynamical pathway is involved when the internal energy of CO (and the corresponding available energy) increases. The KER distributions of O(D) and O(P) show broad internal energy distributions in the CO(XΣ) cofragment, extending up to the maximum allowed by energy but peaking at low KER values. Although not all the observations can be explained at this time, with the aid of available theoretical studies of CO VUV photodissociation and O + CO recombination, it is proposed that following UV absorption, the two lowest lying triplet states, aB and bA, and the ground electronic state are involved in the dynamical pathways that lead to product formation.

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“…Ultraviolet (UV) photo dissociation of carbon dioxide is of considerable importance for atmospheric, planetary, and interstel lar chemistry and has received much attention of the experimentalists. For example, CO 2 photodissociation at 157 nm which involves state to state correlations between CO (ν) and O ( 3 P) has been studied up to now [1][2][3][4][5][6]. Moreover, the reaction of CO (ν) with the elec tronic ground state oxygen atom O ( 3 P) has also been studied with experimental [7][8][9][10][11][12][13][14] and theoretical methods [15,16] so far.…”

Section: Introductionmentioning

confidence: 99%

The potential energy surfaces of the ground and excited states of carbon dioxide molecule

Peng

Zhang

et al. 2014

Russ. J. Phys. Chem.

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Potential energy surfaces (PESs) of the 1 A l ( ), 1 B 2 and 3 B 2 electronic states of CO 2 have been computed as a function of the two bond distances and the bond angle. The calculations were based on the complete active space self consistent field (CASSCF) and multiconfigurational second order perturbation theory (CASPT2) electronic structure models. From our calculations no crossing point between 1 B 2 and 3 B 2 states was found, but there is a crossing point located between 1 B 2 and 3 A 2 state on the PESs. The energy of the crossing point is lie 0.23 eV above the CO + O ( 3 P), which is in agreement with the value of 0.27 eV on the experiment. This implies that the mechanism of the recombination of an oxygen atom with a carbon monoxide molecule: CO(X 1 Σ + , ν) + O( 3 P) 3 C 1 C CO(X 1 Σ + , ν = 0) + O( 1 D) may occur through the 3 A 2 state crossing the 1 B 2 state. The equilibrium geometries and adiabatic excitation energies of 1,3 B 2 , 1,3 A 2 states of CO 2 were reported and discussed in this paper, too.

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Product angular anisotropy in CO2 photodissociation at 157 nm

Cited by 23 publications

References 9 publications

Metastable oxygen atom detection using rare gas matrices

Metastable oxygen atom detection using rare gas matrices

Temperature dependence of the photodissociation of CO2 from high vibrational levels: 205-230 nm imaging studies of CO(X1Σ+) and O(3P, 1D) products

The potential energy surfaces of the ground and excited states of carbon dioxide molecule

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