Branching Ratios of the N(D-2(3/2)0) and N(D-2(5/2)0) Spin-Orbit States Produced in the State-Selected Photodissociation of N-2 Determined Using Time-Sliced Velocity-Mapped-Imaging Photoionization Mass Spectrometry (TS-VMI-PI-MS)

doi:10.1021/acs.jpca.8b11691

	Branching Ratios of the N(D-2(3/2)0) and N(D-2(5/2)0) Spin-Orbit States Produced in the State-Selected Photodissociation of N-2 Determined Using Time-Sliced Velocity-Mapped-Imaging Photoionization Mass Spectrometry (TS-VMI-PI-MS)
	Jackson, William M.3; Ng, Cheuk-Yiu 3; Kalogerakis, Konstantinos S.1; Liu, Kai 2; Chang, Yih Chung 3
刊名	JOURNAL OF PHYSICAL CHEMISTRY A
	2019-03-28
卷号	123 期号:12 页码:2289-2300
ISSN号	1089-5639
DOI	10.1021/acs.jpca.8b11691
英文摘要	Branching ratios for N(D-2(3/2)0) and N(D-2(5/2)0) produced by predissociation of state selected excited nitrogen molecules in the vacuum ultraviolet region have been measured for the first time. The quantum numbers of the excited nitrogen molecule are defined by selective excitation of the nitrogen molecule in the Franck-Condon region from the ground electronic, (1)Sigma(+)(g), vibrational, v '', and rotational, J '' state to an excited E-u', v', J' state with a tunable vacuum ultraviolet, VUV1 laser. The neutral atoms produced by predissociation from this excited state are then selectively ionized with a second tunable VUV2 laser. Measurement of the relative populations of these two atoms formed in their spin-orbit states defines the quantum states for the atomic products. This means that the wave functions of the initial state and knowledge of the relative yields define all the experimental parameters for this series of unimolecular reactions. The ions formed by VUV2 are mass analyzed with a time-of-flight mass spectrometer and detected with a time slice velocity ion imaging mass spectrometer. In this manner, we can determine the recoil velocity associated with the predissociation process. Two different techniques are used to determine the spin-orbit ratios, namely, resonant VUV photoionization (RVUV-PI) spectroscopy and total kinetic energy release (TKER) spectroscopy determined from the image produced when the atoms are selectively ionized by VUV2 in the interaction region. The TKER spectra obtained from the lines at 110 296.25 and 110 304.96 cm(-1) that couple to a newly discovered autoionization line at 129 529.4255 +/- 0.0015 cm(-1) prove that the lines observed in this region originate from the N(D-2(3/2)0) and N(D-2(5/2)0) atoms. Two other lines in this region at 110 286.20 and 110 299.89 cm(-1) originate from the nitrogen N(S-4(3/2)0) that is photoionized in a 1+ 1 VUV-UV resonant multiphoton ionization process. The spin-orbit branching ratios have been evaluated for valence and Rydberg electronic excited states from 104 129.4 to 118 772.1 cm(-1), and it shows that they are independent of the rotational and vibrational quantum numbers. They are not appreciably affected by the symmetry properties of the wave function in the Franck-Condon region of the excited states. In the energy region below 117 153.8 cm(-1) the pathways at long internuclear distances appear to determine [N(D-2(3/2)0)]/[N(D-2(5/2)0)] branching ratios of similar to 0.38, similar to 0.62, and similar to 1.04. At higher energies, TKER and RVUV-PI spectroscopy have been used to show that the average fraction of the N(D-2(3/2)0) and N(D-2(5/2)0) atoms produced in the spin-allowed channels that produce two N(D-2(J)0) is 0.85 versus 0.15 for spin-forbidden channels. The importance and need for this information for comparison with theory and applications in astrochemistry are briefly discussed.
资助项目	NSF[CHE-1301501] ; NSF[AST-1410297]
WOS关键词	PREDISSOCIATION MECHANISMS ; (1)PI(U) ; YIELDS
WOS研究方向	Chemistry ; Physics
语种	英语
出版者	AMER CHEMICAL SOC
WOS记录号	WOS:000463116200001
资助机构	NSF ; NSF ; NSF ; NSF ; NSF ; NSF ; NSF ; NSF
内容类型	期刊论文
源URL	[http://ir.wipm.ac.cn/handle/112942/13933]
专题	中国科学院武汉物理与数学研究所
通讯作者	Jackson, William M.; Ng, Cheuk-Yiu
作者单位	1.SRI Int, Ctr Geospace Studies, 333 Ravenswood Ave, Menlo Pk, CA 94025 USA 2.Chinese Acad Sci, Wuhan Inst Phys & Math, Wuhan 430071, Hubei, Peoples R China 3.Univ Calif Davis, Dept Chem, Davis, CA 95616 USA
推荐引用方式 GB/T 7714	Jackson, William M.,Ng, Cheuk-Yiu,Kalogerakis, Konstantinos S.,et al. Branching Ratios of the N(D-2(3/2)0) and N(D-2(5/2)0) Spin-Orbit States Produced in the State-Selected Photodissociation of N-2 Determined Using Time-Sliced Velocity-Mapped-Imaging Photoionization Mass Spectrometry (TS-VMI-PI-MS)[J]. JOURNAL OF PHYSICAL CHEMISTRY A,2019,123(12):2289-2300.
APA	Jackson, William M.,Ng, Cheuk-Yiu,Kalogerakis, Konstantinos S.,Liu, Kai,&Chang, Yih Chung.(2019).Branching Ratios of the N(D-2(3/2)0) and N(D-2(5/2)0) Spin-Orbit States Produced in the State-Selected Photodissociation of N-2 Determined Using Time-Sliced Velocity-Mapped-Imaging Photoionization Mass Spectrometry (TS-VMI-PI-MS).JOURNAL OF PHYSICAL CHEMISTRY A,123(12),2289-2300.
MLA	Jackson, William M.,et al."Branching Ratios of the N(D-2(3/2)0) and N(D-2(5/2)0) Spin-Orbit States Produced in the State-Selected Photodissociation of N-2 Determined Using Time-Sliced Velocity-Mapped-Imaging Photoionization Mass Spectrometry (TS-VMI-PI-MS)".JOURNAL OF PHYSICAL CHEMISTRY A 123.12(2019):2289-2300.