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Imaging Based on Absorption and Ion Detection Methods
Published in Helmut H. Telle, Ángel González Ureña, Laser Spectroscopy and Laser Imaging, 2018
Helmut H. Telle, Ángel González Ureña
Toward the end of the 1980s, Chandler and Houston (1987) developed a new imaging technique for elucidating chemical reaction dynamics. They demonstrated the viability and advantages of the novel approach with an experiment, in which they imaged the spatial distribution of (laser-ionized) photodissociation products, produced by laser photolysis of methyl iodide; they referred to the method as to photofragment ion imaging or—if applied to the study of chemical reaction products—as product reaction imaging.
VUV photodissociation of DNCO: dynamics of the D atom elimination channel
Published in Molecular Physics, 2021
Ting Xie, Shu Su, Shengrui Yu, Zijie Luo, Zhichao Chen, Xingan Wang, Kaijun Yuan, Xueming Yang
Compared to the intense number of photolysis experiments on HNCO, much less photodissociation information is available for the deuterated analogous DNCO system. In 1993, Bohn et al. investigated the vibrational distribution in product ND (a1Δ, v′′) radical following photolysis of DNCO at 193 nm [36]. In 1996, Brownsword et al. studied the photodissociation dynamics of room temperature DNCO at 193 and 248 nm using the LIF pump–probe technique, the product D atom quantum yields were measured and the corresponding angular anisotropy distribution was determined [37]. Sanov [26] examined the photodissociation of H(D)NCO at 243.1 nm using the photofragment ion imaging technique, a similar trend of recoil anisotropy was observed in H + NCO(X2Π) and D + NCO(X2Π) channels. The photodissociation dynamics of HNCO and DNCO focused on the H/D atom elimination channel at the Lyman-α wavelength was studied by Brownsword et al. [34] using LIF technique. The H/D atom Doppler profile was described and the corresponding dissociation mechanism was discussed.
Photodissociation study of spatially oriented (R)-3-bromocamphor by the hexapole state selector
Published in Molecular Physics, 2022
Hsiu-Pu Chang, Masaaki Nakamura, Toshio Kasai, King-Chuen Lin
In this work, we used the electrostatic hexapole combined with another electrostatic orienting field to orient (R)-3-bromocamphor molecules and dissociated the molecule with a linearly polarised laser. Br*(2P1/2) and Br(2P3/2) products were detected by the same laser at 233.95 and 233.62 nm via (2 + 1) REMPI, respectively. 3-Bromocamphor is a bulky and heavy biomolecular derivative has not been tested for spatial orientation control with hexapole thus far. In this report, it will be shown that the 3-bromocamphor molecules are oriented along the orientation electric field, and its photodissociation dynamics will be discussed based on the result of photofragment ion imaging experiments of the oriented molecules. Considering the possible conditions to distinguish the chirality on the ion images, 3-bromocamphor can be regarded as a proper candidate because of its inherent high molecular mass and consequent large moment of inertia. This makes the conservation of rotational state bulky, heavy and consists of a relatively large momentum of inertia which can permit it to exit from the hexapole in the same rotational state. Besides, it is a derivation of biomolecule, which contains a complex-carbon skeleton. (1R)-(+) bromocamphor without orientation has been studied by inducing a circularly polarised light to obtain the photoelectron spectrum and successfully distinguished enantiomers from different helicity of the light [20–23]. In Section 2, the combination between hexapole and the velocity map imaging is explicitly illustrated, including the experimental design and the experimental parameters. In Section 3, the obtained results are demonstrated and the dissociation dynamics of (R)-(3)-bromocamphor is discussed. Finally, we give the photodissociation dynamics of (R)-3-bromocamphor, as conclusion in Section 4.