Near UV photodissociation of CD3SCD3: CD3 fragment (v, J) vector correlations

Barr, Jonathan; Torres, M. Inés; Bañares, Luis; Verdasco, J. E.; Aoiz, F. J.

doi:10.1016/s0009-2614(03)00632-8

Cited by 8 publications

(29 citation statements)

References 27 publications

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“…Although far from providing a comprehensive analysis, forward simulations of the polarizationdependent REMPI spectra provide strong evidence that the proposed axial impulsive model adequately describes the dissociation mechanism. As was suggested to be the case in a previous study, 9 the analysis here indicates that the J vector does not have cylindrical symmetry about v. Figure 9 shows a schematic diagram of the dissociating parent DMS molecule. Strictly speaking, because the model impulse passes through the center of mass of the methyl fragment, only vibrational motion of the excited parent molecule can induce its rotational excitation.…”

Section: Discussionsupporting

confidence: 61%

“…As has been shown in previous work, 9 this apparent disadvantage of the detection system is particularly useful for the characterization of (µ, v, J) correlations.…”

Section: Methodsmentioning

confidence: 67%

“…Because more than one excited state must usually be considered upon absorption at ultraviolet wavelengths, the influence of nonadiabatic interactions on product observables has attracted particular attention. An interesting example that has been the subject of recent theoretical 4 and experimental [5][6][7][8][9] work is provided by the photodissociation of CH 3 SCH 3 (DMS) in its first absorption band (∼215-230 nm). The electronic configuration of DMS in its ground state can be written as where the highest occupied (nonbonding) 3b 1 molecular orbital is dominated by the 3p x orbital of atomic sulfur, directed perpendicular to the C-S-C plane.…”

Section: Introductionmentioning

confidence: 99%

“…[5][6][7][8] Although the energy partitioning and anisotropy provide a coarse-grained picture, understanding of the photodissociation mechanism can be greatly enhanced by specifying the correlation between the vectors J, the angular momentum, and v, the recoil velocity of the fragments, in a molecular frame defined by µ, the transition dipole moment of the parent molecule at the time of excitation. To this end, a recent study 9 of DMS in the first absorption band (at 219 nm) sought to characterize the laboratory-frame (v, J) alignment of the methyl photofragments immediately after dissociation. Invoking an impulsive dissociation model, where the fragments recoil axially along the CH 3 S-CH 3 bond, core-sampled 19 REMPI spectra of the nascent fragments were adequately simulated.…”

Section: Introductionmentioning

confidence: 99%

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Photodissociation Dynamics of Dimethyl Sulfide Following Excitation within the First Absorption Band

et al. 2004

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The technique of resonance-enhanced multiphoton ionization with time-of-flight mass spectrometry (REMPI-TOF MS) has been used to study the photodissociation of fully deuterated dimethyl sulfide (CD 3 SCD 3 ) following excitation at several wavelengths within the first absorption band (215-229 nm). Analysis of measured time-of-flight profiles of the nascent CD 3 products indicates a strongly anisotropic photodissociation, with approximately 70-80% of the available energy appearing as fragment recoil translation. A hybrid statistical-impulsive dissociation model predicts a photolysis wavelength dependence of the translational energy release that compares favorably with experiment, supporting the suggestion (Manaa, M. R.; Yarkony, D. R. J. Am. Chem. Soc. 1994, 116, 11444) that both the 1 1 A′′ and 2 1 A′′ excited states play an important role in the photodissociation process. An analysis of nascent CD 3 (µ, v, J) vector correlations, where the fragments are assumed to recoil axially along the CD 3 S-CD 3 bond, adequately accounts for the observed probe laser polarization dependence of velocity-selected REMPI spectra. The weak observed rotational excitation of the methyl fragments originates from zero-point vibrational motion of the dissociating parent molecule.

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Section: Discussionsupporting

confidence: 61%

“…As has been shown in previous work, 9 this apparent disadvantage of the detection system is particularly useful for the characterization of (µ, v, J) correlations.…”

Section: Methodsmentioning

confidence: 67%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Photodissociation Dynamics of Dimethyl Sulfide Following Excitation within the First Absorption Band

et al. 2004

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“…8 The analysis of the dissociation anisotropy of DMS provided β parameters close to the limiting value of -1 (for a pure perpendicular transition) while the full µ-v-J vector correlation analysis, i.e. the correlation between the transition dipole moment µ, the fragment recoil direction v, and the total angular momentum J of the detected fragment, indicated that the J vector does not have cylindrical symmetry about the recoil velocity v. 8,9 Such result is in disagreement with a pure impulsive model, which considers only in-plane and out-of-plane rocking modes. It was suggested that the parent ν 3 C-S-C deformation mode, tentatively introduced in the hybrid model, could explain the alignment of the J vector.…”

Section: Introductionmentioning

confidence: 99%

Photodissociation Dynamics and Stereodynamics of Methyl Mercaptan and Dimethyl Sulfide from the Second Absorption Band at 201 and 210 nm

et al. 2019

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The role of promoting and spectator modes vs. energy randomization in nonadiabatic dynamics is interrogated in the photodissociation of methyl mercaptan, CH 3 SH, and dimethyl sulde, CH 3 SCH 3 or DMS, in the second absorption band. The primary 1 CH 3 (ν) radicals produced in the dissociation of both systems at 210 nm have been resonantly detected in slice-imaging experiments and the corresponding translational energy and angular distributions have been obtained. The stereodynamical information provided by Dixon's bipolar moments in conjunction with the energy partitioning among the dierent degrees of freedom of the primary CH 3 (ν) products oers a panoramic picture of the photodissociation process of both systems. The remarkable similitude found between the two systems related to both vector correlations and internal energy content of the corresponding counterparts − SH for methyl mercaptan and SCH 3 for DMS − indicates that despite the diabaticity of the process, no ecient energy randomization of the available energy takes place. More specically, only the parent vibrational modes whose participation in the initial absorption step is imposed by the conical intersection − i.e. the promoting modes − are adiabatically preserved during the process, while the rest of the vibrational modes play the spectator role. The results for both molecules at 210 nm are complemented with experiments carried out for DMS at 201 nm to explore the internal mechanism of the conical intersection in dierent zones of the absorption region.

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Photodissociation dynamics of dimethyl sulfoxide-d6 at 210 nm: experimental evidence for a prompt anisotropic CD3 channel

Amaral¹,

Torres²,

Pino³

et al. 2004

Chemical Physics Letters

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Near UV photodissociation of CD3SCD3: CD3 fragment (v, J) vector correlations

Cited by 8 publications

References 27 publications

Photodissociation Dynamics of Dimethyl Sulfide Following Excitation within the First Absorption Band

Photodissociation Dynamics of Dimethyl Sulfide Following Excitation within the First Absorption Band

Photodissociation Dynamics and Stereodynamics of Methyl Mercaptan and Dimethyl Sulfide from the Second Absorption Band at 201 and 210 nm

Photodissociation dynamics of dimethyl sulfoxide-d6 at 210 nm: experimental evidence for a prompt anisotropic CD3 channel

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