Photodissociation of Cl2O at 248 and 308 nm

Moore, Teresa A.; Okumura, Mitchio; Minton, Timothy K.

doi:10.1063/1.474706

Cited by 24 publications

(24 citation statements)

References 8 publications

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“…If a speed dependence exists, the variations of with V should be smaller than (0.2, which is less than the variation from 0.7 to 1.5 observed by Okumura and co-workers in the 248 nm dissociation. 30 Again, there is qualitative agreement of our data with the values of Tanaka et al, who observed mean anisotropy parameters of 1.2 ( 0.2 for both spin-orbit states. 14 In fact, their value might be more reliable than ours in view of the focusing conditions in our experiment.…”

Section: B 53 Ev Anisotropysupporting

confidence: 93%

Photodissociation Dynamics of Cl₂O: Interpretation of Electronic Transitions

2004

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The photodissociation of Cl 2 O has been investigated for adjacent regions in the first and the second absorption bands, respectively, at dissociation wavelengths of 5.3 and 6.0 eV. Chlorine and oxygen atoms were stateselectively detected by resonance-enhanced multiphoton ionization. Chlorine fragment kinetic energy and spatial distributions were determined from time-of-flight profile analysis. At 5.3 eV, kinetic energy distributions are broad and bimodal and differ significantly for the two spin-orbit states Cl*( 2 P 1/2 ) and Cl( 2 P 3/2 ). The decay is characterized by a positive anisotropy parameter of 0.7 ( 0.2. Excitation proceeds via the transitions 10a 1 r 7b 2 and 10a 1 r 9a 1 . The data are in agreement with generating ClO(X) + Cl*( 2 P 1/2 ) as primary fragments. At 6.0 eV, kinetic energy distributions are narrow and structureless and are similar for the two spin-orbit states Cl*( 2 P 1/2 ) and Cl( 2 P 3/2 ). The decay is characterized by a small positive anisotropy parameter of 0.2 ( 0.2. The main dissociation channel is the three-body decay into 2Cl + O. The decay mechanism is of an asynchronous concerted type. The data suggest the primary production of ClO(A) + Cl( 2 P J ). Excitation proceeds mainly via the transition 8b 2 r 7b 2 . The results show the need for refined theoretical calculations.

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Section: B 53 Ev Anisotropysupporting

confidence: 93%

Photodissociation Dynamics of Cl₂O: Interpretation of Electronic Transitions

2004

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“…It is known that the Hartley band ͑200-300 nm͒ of O 3 originates from excitation of the strongly repulsive branch of the B state and the involved electronic states are either repulsive or excited above their thresholds. The near ultraviolet photodissociation of Cl 2 O has been investigated in molecular beams [24][25][26][27] and in a gas cell; 28 the results indicate unity dissociation yield under low pressure conditions. 18,19 A similar argument can be applied to ClOOCl because ab initio calculations [20][21][22] and molecular beam experiments 23 suggest fast dissociation.…”

Section: Resultsmentioning

confidence: 99%

Photodissociation cross sections of ClOOCl at 248.4 and 266 nm

Lien

Lin

Chen

et al. 2009

The Journal of Chemical Physics

104

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This study utilized a mass-resolved detection of ClOOCl to determine its photodissociation cross section, which is the product of the absorption cross section and dissociation quantum yield. An effusive molecular beam of ClOOCl was generated and its photodissociation probability was determined through measuring the decrease in the ClOOCl beam intensity upon laser irradiation. By comparing with a reference molecule, the absolute cross sections of ClOOCl were obtained without knowing its absolute concentration. The determined cross section of ClOOCl at 248.4 nm is (8.85+/-0.42)x10(-18) cm(2) at 200 K, significantly larger than previously reported values. The temperature dependence of the cross section was investigated at 248.4 nm in the range of 160-260 K; only a very small and negative temperature effect was observed. Because 248.4 nm is very close to the peak of the UV absorption band of ClOOCl, this work provides a new calibration point for normalizing relative absorption spectra of ClOOCl. In this work, the photodissociation cross section at 266 nm and 200 K was also reported to be (4.13+/-0.21)x10(-18) cm(2).

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“…Furthermore, these authors detected a transient absorption spectrum, which they assigned to a long-lived metastable triplet state of Cl 2 O. However Moore et al [550] estimated the lifetime of this metastable excited state to be much shorter. Chichinin [167] and Tanaka et al [773], also found evidence of ground state ( 2 P 3/2 ) and spin-orbit excited ( 2 P 1/2 ) atomic chlorine products.…”

Section: -95mentioning

confidence: 99%

“…NH + NO. The recommendation is derived from the room temperature results of Hansen et al [550], Cox et al [313] and Harrison et al [553]. The temperature dependence is from Harrison et al (Table: 92-20, Note: 92-20) Back to Table C30.…”

Section: -41mentioning

confidence: 99%