An Experimental Study on the Photochemistry and Vibrational Spectroscopy of Three Isomers of Cl2O2 Isolated in Cryogenic Matrixes

Jacobs, Juergen; Kronberg, Marc; Mueller, H. S. P.; Willner, Helge

doi:10.1021/ja00082a038

Cited by 73 publications

(103 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…b 321 cm −1 and upper limit of 342 cm −1 from different ab initio calculations (Lee et al, 1992), lower limit of 310 cm −1 from force field calculations (Jacobs et al, 1994). c measured by (Jacobs et al, 1994), in good agreement with other experiments (Burkholder et al, 1990;Cheng and Lee, 1989). Measurements are rather exact and uncertainties of these higher frequencies are not significant for the calculations in the temperature range relevant to this study.…”

Section: Introductionsupporting

confidence: 84%

“…The lower limit used here represents the lowest value found in the literature (Jacobs et al, 1994). b 321 cm −1 and upper limit of 342 cm −1 from different ab initio calculations (Lee et al, 1992), lower limit of 310 cm −1 from force field calculations (Jacobs et al, 1994). c measured by (Jacobs et al, 1994), in good agreement with other experiments (Burkholder et al, 1990;Cheng and Lee, 1989).…”

Section: Introductionsupporting

confidence: 79%

“…As all reported values from ab initio (e.g. Lee et al, 1992) and force field calculations (Jacobs et al, 1994) fall below 127 cm −1 , we deem it unlikely that the frequency should be higher. The lower limit used here represents the lowest value found in the literature (Jacobs et al, 1994).…”

Section: Introductionmentioning

confidence: 83%

“…Lee et al, 1992) and force field calculations (Jacobs et al, 1994) fall below 127 cm −1 , we deem it unlikely that the frequency should be higher. The lower limit used here represents the lowest value found in the literature (Jacobs et al, 1994). b 321 cm −1 and upper limit of 342 cm −1 from different ab initio calculations (Lee et al, 1992), lower limit of 310 cm −1 from force field calculations (Jacobs et al, 1994).…”

Section: Introductionmentioning

confidence: 85%

See 3 more Smart Citations

Understanding the kinetics of the ClO dimer cycle

et al. 2007

View full text Add to dashboard Cite

Abstract. Among the major factors controlling ozone loss in the polar vortices in winter/spring is the kinetics of the ClO dimer catalytic cycle. Here, we propose a strategy to test and improve our understanding of these kinetics by comparing and combining information on the thermal equilibrium between ClO and Cl 2 O 2 , the rate of Cl 2 O 2 formation, and the Cl 2 O 2 photolysis rate from laboratory experiments, theoretical studies and field observations. Concordant with a number of earlier studies, we find considerable inconsistencies of some recent laboratory results with rate theory calculations and stratospheric observations of ClO and Cl 2 O 2 . The set of parameters for which we find the best overall consistency -namely the ClO/Cl 2 O 2 equilibrium constant suggested by Plenge et al. (2005), the Cl 2 O 2 recombination rate constant reported by Nickolaisen et al. (1994) and Cl 2 O 2 photolysis rates based on absorption cross sections in the range between the JPL 2006 assessment and the laboratory study by Burkholder et al. (1990) -is not congruent with the latest recommendations given by the JPL and IUPAC panels and does not represent the laboratory studies currently regarded as the most reliable experimental values. We show that the incorporation of new Pope et al. (2007) Cl 2 O 2 absorption cross sections into several models, combined with best estimates for other key parameters (based on either JPL and IUPAC evaluations or on our study), results in severe model underestimates of observed ClO and observed ozone loss rates. This finding suggests either the existence of an unknown process that drives the partitioning of ClO and Cl 2 O 2 , or else some unidentified problem with either the laboratory study or numerous measurements of atmospheric ClO. Our mechanistic understanding of the ClO/Cl 2 O 2 system is grossly lacking, with severe implications for our ability to simulate both present and future polar ozone depletion.

show abstract

Section: Introductionsupporting

confidence: 84%

Section: Introductionsupporting

confidence: 79%

Section: Introductionmentioning

confidence: 83%

Section: Introductionmentioning

confidence: 85%

See 2 more Smart Citations

Understanding the kinetics of the ClO dimer cycle

et al. 2007

View full text Add to dashboard Cite

show abstract

“…The temperature dependence implied by n=−2.29 is higher, although it still agrees within its uncertainty given by the fit. Another possible explanation for this effect is the formation of different isomers of Cl 2 O 2 , which has been suggested in numerous theoretical (Fangstrom et al, 1998;Han et al, 1998;Lee et al, 1992;Li and Ng, 1997;McGrath et al, 1990;Stanton et al, 1991;Zhu and Lin, 2003) and experimental (Jacobs et al, 1994;Müller and Willner, 1992;Plenge et al, 2004a;Schwell et al, 1996) studies on the stability of the three stable Cl 2 O 2 isomers, namely chlorine peroxide (ClOOCl), chloryl chloride (ClClO 2 ) and chlorine chlorite (ClOClO). Slanina and Uhlík have presented calculations showing that the relative stabilities of the Cl 2 O 2 isomers and hence the composition of the equilibrium isomeric mixture depends on temperature (Slanina and Uhlik, 1991b), and that this has direct effects on the temperature dependence of K EQ (Slanina, 1992;Slanina and Uhlik, 1991a).…”

Section: Fitmentioning

confidence: 98%

A re-evaluation of the ClO/Cl<sub>2</sub>O<sub>2</sub> equilibrium constant based on stratospheric in-situ observations

Hobe¹,

Grooß²,

Müller³

et al. 2005

Atmos. Chem. Phys.

View full text Add to dashboard Cite

Abstract. In-situ measurements of ClO and its dimer carried out during the SOLVE II/VINTERSOL-EUPLEX and ENVISAT Validation campaigns in the Arctic winter 2003 suggest that the thermal equilibrium between the dimer formation and dissociation is shifted significantly towards the monomer compared to the current JPL 2002 recommendation. Detailed analysis of observations made in thermal equilibrium allowed to re-evaluate the magnitude and temperature dependence of the equilibrium constant. A fit of the JPL format for equilibrium constants yields K EQ =3.61×10 −27 exp(8167/T ), but to reconcile the observations made at low temperatures with the existing laboratory studies at room temperature, a modified equation, K EQ =5.47×10 −25 (T /300) −2.29 exp(6969/T ), is required. This format can be rationalised by a strong temperature dependence of the reaction enthalpy possibly induced by Cl 2 O 2 isomerism effects. At stratospheric temperatures, both equations are practically equivalent. Using the equilibrium constant reported here rather than the JPL 2002 recommendation in atmospheric models does not have a large impact on simulated ozone loss. Solely at large zenith angles after sunrise, a small decrease of the ozone loss rate due to the ClO dimer cycle and an increase due to the ClO-BrO cycle (attributed to the enhanced equilibrium ClO concentrations) is observed, the net effect being a slightly stronger ozone loss rate.

show abstract

Density functional study of chlorine-oxygen compounds related to the ClO self-reaction

Fängström¹,

Edvardsson

Ericsson

et al. 1998

Int. J. Quant. Chem.

View full text Add to dashboard Cite

Geometrical parameters, vibrational frequencies, relative stabilities, and dissociation energies of the three stable Cl O isomers and the OClO and ClOO radicals 2 2 Ž . were investigated by density functional theory DFT . The present analysis shows that DFT using hybrid functionals is capable of describing these systems to at least the same degree of accuracy as ab initio methods. The average absolute bond-length deviation of ClClO , ClOOCl, and ClO from experimental results is 0.024r0.027 A, with a maximum 2 2d eviation for the dichlorine peroxide O O bond equal to 0.072r0.063 A, for the B3PW91 and B3LYP functionals, respectively. The average absolute bond-angle deviation for the hybrid functionals is 0.8Њ. Harmonic vibrational frequencies calculated with DFT give for all Cl O compounds good agreement with experiments. The dissociation energies of ClOOCl, OClO, and ClOO were found to be in good agreement with experiments, the average error being less than 1.2 kcalrmol. The two isomers chloryl Ž . Ž . chloride ClClO and dichlorine peroxide ClOOCl were found to be approximately 9 2 Ž. kcalrmol more stable than the chlorine chlorite ClOClO isomer. The ClOO isomer is predicted to be 3.0 kcalrmol more stable than OClO, in accordance with the experimental value of 4 kcalrmol.

show abstract

An Experimental Study on the Photochemistry and Vibrational Spectroscopy of Three Isomers of Cl2O2 Isolated in Cryogenic Matrixes

Cited by 73 publications

References 0 publications

Understanding the kinetics of the ClO dimer cycle

Understanding the kinetics of the ClO dimer cycle

A re-evaluation of the ClO/Cl<sub>2</sub>O<sub>2</sub> equilibrium constant based on stratospheric in-situ observations

Density functional study of chlorine-oxygen compounds related to the ClO self-reaction

Contact Info

Product

Resources

About

An Experimental Study on the Photochemistry and Vibrational Spectroscopy of Three Isomers of Cl2O2 Isolated in Cryogenic Matrixes

Cited by 73 publications

References 0 publications

Understanding the kinetics of the ClO dimer cycle

Understanding the kinetics of the ClO dimer cycle

A re-evaluation of the ClO/Cl&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;2&lt;/sub&gt; equilibrium constant based on stratospheric in-situ observations

Density functional study of chlorine-oxygen compounds related to the ClO self-reaction

Contact Info

Product

Resources

About

A re-evaluation of the ClO/Cl<sub>2</sub>O<sub>2</sub> equilibrium constant based on stratospheric in-situ observations