Imaging Photodissociation Dynamics of Excited SiO Molecules at 193 nm with Laser Ablation Supersonic Beam
SiO is a wide-spread molecule found in interstel-lar space.Previous research has primarily focused on its spectroscopy,while its photodissociation dynamics is elusive to study due to high dissocia-tion energy.Using time-sliced ion velocity imag-ing technique,we observed the Si(3P)+O(3P)photodissociation process resulting from the exci-tation of highly vibrationally excited SiO(X1E+,v=13-18)molecules to the SiO(A1∏,E1∑+)states at 193 nm.The vibrationally excited SiO molecules were generated via laser ablation of sili-con rod with the collision of the oxygen molecular beam acting as carrier gas and reaction gas.The bond dissociation energy De(Si-O)is deter-mined to be 67253±110 cm-1(8.34±0.01 eV)based on the kinetic energy distribution spec-trum.The SiO photodissociation study has deepened our understanding of the mechanisms of silicon chemistry for silica-rich rocky meteors as they burn in the Earth's atmosphere,and the dissociation of SiO from ablation of meteoroids following ultraviolet photon absorption.
PhotodissociationSiOVibrational excitationLaser ablationTime-sliced ion velocity imaging
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