Photodissociation of 2-Bromobutane at ∼265 nm by Ion-velocity Map Imaging Technique

Zhou, Dongwen; Mao, Rui; Zhang, Limin; Zhang, Qun; Chen, Yang

doi:10.1088/1674-0068/25/04/373-378

Cited by 2 publications

(1 citation statement)

References 27 publications

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“…Both photofragments can be observed separately by resonance-enhanced multiphoton ionization (REMPI). Recent studies with nonoriented molecules have reported 38,39 that these two states show independent photofragment distributions and report two velocity components for each state. Regarding the faster components, both velocity and angular distributions are characterized by our results, while the slower components were not observed as such in our experiment, but slow to arise to the overlapped signals in the time domain, originated by the two isotopes of bromine atom, 79 Br and 81 Br, occurring in nature with approximately equal abundance; in the present experiment the two signals are almost isolated on sliced images by using the weak ion extraction field.…”

Section: Introductionmentioning

confidence: 99%

Hexapole-Oriented Asymmetric-Top Molecules and Their Stereodirectional Photodissociation Dynamics

et al. 2016

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Abstract.Molecular orientation is a fundamental requisite in the study of stereodirected dynamics of collisional and photoinitiated processes. In this last decade, variable hexapolar electric filters have been developed and employed for the rotational-state selection and the alignment of molecules of increasing complexity, for which main difficulties are their mass, their low symmetry and the very dense rotational manifold. In this work, for the first time, a complex molecule such as 2-bromobutane, an asymmetric-top containing a heavy atom (the bromine), has been successfully oriented by a weak homogeneous field placed downstream the hexapolar filter.Efficiency of the orientation has been characterized experimentally, by combining time-of-flight measurements and a slice-ion-imaging detection technique. The application is described to the photodissociation dynamics of the oriented 2-bromobutane, which was carried out at a laser wavelength of 234 nm, corresponding to the breaking of the C -Br bond. The Br photofragment is produced in both the ground Br ( 2 P3/2) and the excited Br ( 2 P1/2) electronic states and both channels are studied by the slice imaging technique, revealing new features in the velocity and angular distributions with respect to previous investigations on non-oriented molecules. 3 1. Introduction.

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Section: Introductionmentioning

confidence: 99%

Hexapole-Oriented Asymmetric-Top Molecules and Their Stereodirectional Photodissociation Dynamics

et al. 2016

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Stereodirectional images of molecules oriented by a variable-voltage hexapolar field: Fragmentation channels of 2-bromobutane electronically excited at two photolysis wavelengths

Nakamura

Yang

Lin

et al. 2017

The Journal of Chemical Physics

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The asymmetric-top molecule 2-bromobutane is oriented by means of a hexapole state selector; the angular distribution of the bromine atom photofragment, for the two fine-structure components, is acquired by velocity-map ion imaging. The molecular beam, spatially oriented along the time-of-flight axis, is intersected with a linearly polarized laser, whose polarization is tilted by 45° with respect to the detector surface. To obtain the mixing ratio of the perpendicular and parallel transitions, the fragment ion images and angular distributions can be appropriately simulated to give insight on the population mechanism of the specific electronic state involved at each selected excitation wavelength. The photofragment images obtained at 238.6 nm yielded an asymmetry factor β of 0.67, indicative of the extent of molecular orientation, and an anisotropy parameter β of 1.03, which is a signature of a prevailing parallel transition along the C-Br axis. When the photolysis wavelength is tuned to 254.1 nm, the corresponding angular distribution is less asymmetric (β = 0.24) and the obtained small value β = 0.12 is a characteristic of a predominantly perpendicular transition. The photofragment angular distributions are also affected by hexapole voltage, especially regarding the asymmetry factor, and this aspect provides information on the effect of molecular orientation.

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Photodissociation of 2-Bromobutane at ∼265 nm by Ion-velocity Map Imaging Technique

Cited by 2 publications

References 27 publications

Hexapole-Oriented Asymmetric-Top Molecules and Their Stereodirectional Photodissociation Dynamics

Hexapole-Oriented Asymmetric-Top Molecules and Their Stereodirectional Photodissociation Dynamics

Stereodirectional images of molecules oriented by a variable-voltage hexapolar field: Fragmentation channels of 2-bromobutane electronically excited at two photolysis wavelengths

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