of Xenon Collision Dimers in the VUV Energy Region Rydberg States of Xenon Collision Dimers in the VUV Energy Region Wan-Chun Pan Dept. of Chemistry, National Tsing Hua University
NSRRC 這個工作主要在台灣新竹的NSRRC所進行。Nsrrc屬第三代同步加速器,提供了良好的軟硬x-ray,vuv及ir光源,舊設施已不敷使用,目前正在興建新的儲存環TLS
M. Salvermoser and D. E. Murnick , Appl. Phys. Lett., 83, 8 (2003) Motivation Xe2* excimer : good medium of VUV light source (lamp, laser...) 172 nm M. Salvermoser and D. E. Murnick , Appl. Phys. Lett., 83, 8 (2003)
Electronic Configurations: Xe: [Kr]5s25p6 (1S0) Xe2:(σg5s)2(σu5s)2(σg5p)2(πg5p)4(πu5p)4 (σu5p)2 X1Σg+ First Rydberg State: Xe: 5s25p56s[3/2]1 Xe2: 0u- [dissociation limit: Xe(1S0)+Xe(6s[3/2]1)] Xe2 is an Van der Waals molecule.
Xenon Dimer State= Xenon dimer ion state+ Rydberg electron state R. S. Mulliken, J. Chem. Phys., 52, 5170 (1970) Xenon Dimer States Xenon Atomic States
Xe2 Rydberg States Studied by: Absorption M. C. Castex and N. Damany, Chem. Phys. Lett. 13, 158 (1972) M. C. Castex, Chem. Phys. 5, 448 (1974). M. C. Castex and N. Damany, Chem. Phys. Lett. 24, 437 (1974) Laser induced fluorescence R. H. Lipson, P. E. LaRocque, and B. P. Stoicheff, J. Chem. Phys. 82, 4470 (1985) K. Tsukiyama and T. Kasuya, J. Mol. Spectrosc. 151, 312 (1992) Two-photon excitation W. Gornik, S. Kindt, E. Mathias, and D. Schmidt, J. Chem. Phys. 75, 4595 (1981) P. M. Dehmer, S. T. Pratt, and J. L. Dehmer, J. Chem. Phys. 85, 13 (1986). D. S. Green and S. C. Wallace, J. Chem. Phys. 100, 6129 (1994). S. S. Dimov, J. Y. Cai, and R. H. Lipson, J. Chem. Phys. 101, 10 313 (1994). X. K. Hu, D. M. Mao, S. S. Dimov, and R. H. Lipson, J. Chem. Phys. 106, 9411 (1997). X. K. Hu, D. M. Mao, Y. J. Shi, S. S. Dimov, and R. H. Lipson, J. Chem. Phys. 109, 3944 (1998). “ Xe2 Rydberg states: Energy < 85000 cm-1” > 90000 cm-1
Decay processes of Xe* in gas cell: atomic emission Xe*...Xe (one or multi step(s)) collision dimers Xe* + Xe Xe2* Xe2*Xe2Xe+Xe Xe2*Xe*+XeXe+Xe Xe2*Xe*+XeXe2*’Xe+Xe ...... J. W. Keto et al., J. Chem. Phys. 84, 709 (1986)
Single Photon Excitation Xe2+ cm-1 Xe+Xe+(2P1/2) 108370.80 cm-1 C2 Π 3/2u Xe2+ B2 Π 1/2g B2 Π 3/2g 100k Dissociative ionization: Xe2**Xe++Xe+e- A2 Σ 1/2u Xe+Xe+(2P3/2) 97833.787 cm-1 95k Xe2 * Xe+Xe* (ns, nd, ns’) 90k VUV Single Photon Excitation 85k = = = = Xe2X1 Σg+ Xe(1S0)
Experimental Setup Scanning range:11800-13400 cm-1 R=0.2 cm-1 Xe: 99.999% Pressure: 2-6 torr
Beamline Status of NSRRC 21B Resolution~20000 @10eV with slit =50*100μm
Experimental Station of NSRRC 21B2
Excited Xenon Atomic States State (5p5nl[K]J) Photon Energy (cm-1) 5p513s[3/2]1 96480.620 5p512s[3/2]1 96122.770 5p510d[3/2]1 96045.770 5p510d[1/2]1 95912.880 5p57s’[1/2]1 95800.584 5p511s[3/2]1 95590.970 5p59d[3/2]1 95498.480 5p59d[1/2]1 95228.399 5p510s[3/2]1 94787.084 5p58d[3/2]1 94685.467 5p58d[1/2]1 94228.004 5p55d’[3/2]1 93618.240 5p58s[3/2]1 90932.432
5p5(2P01/2)7s[1/2]1 95 800.584 cm-1 先說明量到氙離子 橫軸是雷射能量 再來解釋無法避免觀測到原子雙光子激發共振的光譜
5p5(2P03/2)10d[1/2]1 95 912.88 cm-1 這兩張圖有點像得到相似的光譜
5p5(2P03/2)11s[3/2]1 95 590.970cm-1 換到s能態
5p5(2P03/2)12s[3/2]1 96 122.77 cm-1 解釋1-19的mark 從低能量到高能量
5p5(2P03/2)13s[3/2]1 96 480.62 cm-1
5p5(2P03/2)10d[3/2]1 96 045.77 cm-1
5p5(2P03/2)9d[3/2]1 95 498.48 cm-1
Characteristics of the Signals The signals appeared at the same IR energy. There’re two different line shapes in these spectra. One is with the FWHM > 10 cm-1, and the other is FWHM < 5 cm-1. Intermediate states with the same angular momentum and [K] gave rise to the similar dimer populations in the spectra.
Single Photon Excitation D2 Σ 1/2g C2 Π 1/2u cm-1 Xe+Xe+(2P1/2) C2 Π 3/2u Xe2+ B2 Π 1/2g B2 Π 3/2g 100k Xe+Xe**(ARS) Xe2** A2 Σ 1/2u Xe+Xe+(2P3/2) 97833.787 cm-1 95k Xe+Xe** (ns, nd, ns’) Xe2 ** Xe2 * 90k VUV SR Single Photon Excitation 85k E(Xe2*)=E[Xe+(2P3/2) ]- E(IR energy) = = Xe2X1 Σg+ Xe(1S0)
E(Xe2*)=E[Xe+(2P3/2) ]- E(IR energy) a 85141.9 cm-1 Chem. Phys. 5, 448 (1974) b 85066.8 cm-1 J. Mol. Spectrosc. 151, 312 (1992) c 84715.7 cm-1 J. Chem. Phys. 117, 3059 (2002) 0/1/2u 0/1/2u 1u 解釋1-19的mark 從低能量到高能量 84500-86000 22
5p5(2P03/2)10d[1/2]1 95 912.88 cm-1 a 85141.9 cm-1 Chem. Phys. 5, 448 (1974) b 85066.8 cm-1 J. Mol. Spectrosc. 151, 312 (1992) c 84715.7 cm-1 J. Chem. Phys. 117, 3059 (2002) 0/1/2u 1u 0/1/2u 23
Summary & Future Works The transitions to Xe2 Rydberg states in the energy region of 84000-86000 cm-1 are observed, and lineshpes are dependence of lifetime of Xe2 states. The lower atomic states will be excited and the formed dimer states would be detected later. The photoemission spectrum will be detected for comfirming the relaxation processes.
Acknowledgement National Science Council (NSC) National Synchrotron Radiation Research Center (NSRRC) National Tsing Hua University Advisors: Dr. I-Chia Chen (NTHU) Dr. Yin-Yu Lee (NSRRC) Co-workers: Mr. Tzu-Ping Huang (NSRRC) Mr. Tzan-Yi Dung Group members of Dr. I-Chia Chen and Dr. Yin-Yu Lee Dr. Shih-Huang Lee and his group members (NSRRC)
Thank you for your attention.