@article {4039,
	title = {Stereodynamic Imaging of Bromine Atomic Photofragments Eliminated from 1-Bromo-2-methylbutane Oriented via Hexapole State Selector},
	journal = {Journal of Physical Chemistry A},
	volume = {123},
	year = {2019},
	pages = {6799-6811},
	abstract = {<p>Both single-laser and two-laser experiments were conducted to look into the ion-imaging of Br*(2P1/2) and Br(2P3/2) photofragmented from 1-bromo-2-methylbutane in the range 232-240 nm via a detection scheme of (2+1) resonance-enhanced multiphoton ionization. The angular analysis of these photofragment distributions yields the anisotropy parameter β = 1.88 {\textpm} 0.06 for the Br* excited state which arises from a parallel transition, while β = 0.63 {\textpm} 0.09 for the Br ground state indicates the contribution from both a perpendicular transition and a non-adiabatic transition. When a hexapole coupled with an orienting field was implemented, the parent molecules are spatially oriented to yield an orientation efficiency |{\guillemotleft}cos θ {\guillemotright}| of 0.15. Besides the χ angle between the recoil velocity v and the transition dipole moment μ, orienting molecules allows for the evaluation of the angle α between v and the permanent molecular dipole moment d. The angular analysis of Br* photofragment distribution yields χ = 11.5{\textdegree} and α in the range from 160{\textdegree} to 180{\textdegree} with weak dependency. In the two-laser experiments, the angular anisotropy of Br photofragment distribution was found to be smaller (0.38 {\textpm} 0.10) when the photolysis wavelength was red-shifted to 240 nm, suggesting the increasing contributions from perpendicular transitions. {\textcopyright} 2019 American Chemical Society.</p>
},
	url = {https://www.scopus.com/record/display.uri?eid=2-s2.0-85068061488\&doi=10.1021\%2facs.jpca.9b04048\&origin=inward\&txGid=5f2a0577b811d506098f1d89c91fd11f},
	author = {Nakamura, M. and Chang, H.-P. and King-Chuen Lin and Kasai, Toshio and Che, Dock-Chil and Palazzetti, Federico and Aquilanti, Vincenzo}
}
