臺灣博碩士論文加值系統

藉由飛秒雷射激發–探測實驗技術與動能解析之飛行時間質譜技術的結合，我們得以觀測acetone及DMSO分子分別在195 nm及200 nm的能量激發下，所引發之光分解反應過程。我們首次完整觀測到這兩種分子在光分解過程中，反應物、過渡態分子及產物隨反應進行的變化量。對於acetone在195 nm的能量激發下，所進行之光分解反應而言，我們探討兩種解離途徑，其一為廣為前人所接受之經由T1能態解離之反應途徑；其二為Diau et al [ChemPhysChem 3, 57 (2002)] 所提出之經由S1能態解離之反應途徑。我們認為激發能量的高低將會影響acetone 會經由S1能態解離或是經由ISC（Intersystem Crossing）轉變至T1能態之後再進行解離，因此也決定光分解反應的途徑。我們的實驗結果顯示，當acetone被激發之S2能態之零點位能面（zero-point energy surface）時，反應將遵循經由S1能態之解離途徑。針對實驗所觀察到的特殊現象，我們也進一步提供與一般廣為接受之反應機制不同的觀點。
DMSO與acetone具有類似的結構及組成，只有一個原子的不同，卻使得其光分解反應與acetone完全不同。由於我們是首次以飛秒雷射技術進行DMSO之氣態光分解反應研究，因此能夠提供產物生成時間的資訊。我們針對前人所提出之可能的反應機制做個別的探討，並經由比較傳統產物動能譜與SO產物不尋常之高振動態分佈的實驗結果，我們提出一較為特殊之接近同步（nearly-concerted）解離與基態解離共存之反應機制。但是我們同時也指出實驗上的不足之處，希望能夠加強理論計算對激發態的瞭解以及應用其他實驗技術，能對DMSO的光分解機制有更深入的認識。

Acknowledgements
Abstract
Contents i
List of Figures iv

Chapter I–Introduction

Chapter II–Experimental System and Techniques
1. Pump-Probe Technique
2. Ultrafast Femtosecond Laser System
(A) The Generation of Femtosecond Laser
(B) Amplification of Femtosecond Laser
(C) Wavelength Tunability of Femtosecond Laser
3. Molecular Beam Apparatus
4. Time-Of-Flight Mass Spectrometer
5. Kinetic-Energy Resolved Time-Of-Flight Mass Spectrometry（KETOF Spectrometry）
6. Experimental System Setup
7. Data Acquisition System
8. Data Analysis Method
9. References

Chapter III–Ultrafast Photodissociation Dynamics of Acetone S2 State
1. Introduction
(A) The Acetone S1 State
(B) The Acetone S2 State
2. Experimental Section
3. Experimental Results
(A) The Parent Transient
(B) The Acetyl Transients
(C) The Methyl Transients
(D) KETOF Spectra of Methyl Products
(E) KETOF Spectra of Short-lived Acetyl Intermediate
(F) Kinetic-energy Selected Methyl Transients
(G) Laser Irradiance Dependences
(H) Molecular Beam Condition Dependences
4. Analyses and Discussions
(A) Initial State Dynamics
(B) The Acetyl Intermediate
(C) The Methyl Transients
(D) KETOF Spectra：The Primary and Secondary Components
(E) Three-body Dissociation Kinematic Modeling
(F) Primary Dissociation Dynamics
(G) Secondary Dissociation Dynamics
(H) Isotope Effects
5. Conclusions
6. References

Chapter IV–Ultrafast Photodissociation Dynamics of DMSO at 200 nm
1. Introduction
2. Experimental Section
3. Experimental Results
(A) The Parent Transient
(B) The Intermediate Transient
(C) The Methyl Transients
(D) KETOF Spectra of Methyl Products
4. Data Analyses
(A) Initial State Dynamics
(B) The CH3SO Intermediate
(C) The Methyl Products
(D) The Methyl KETOF Spectra
5. Discussions of Three Photodissociation Mechanisms
(A) Simple Stepwise Mechanism
(B) The Parallel Primary and Ground-state Secondary Dissociation
(C) The Nearly-concerted Three-body and Ground-state Dissociation Mechanism
6. Conclusions
7. References

Chapter V–Remarking Conclusions

1. S. Arrhenius, Z. Phys. Chem. 4, 226 (1889)
2. a) H. Eyring, J. Chem. Phys. 3, 107 (1935) b) H. Eyring, J. Chem. Phys. 3, 492 (1935)
3. M. G. Evans, M. Polanyi, Trans. Faraday Soc. 31, 875 (1935)
4. H. Hartridge, F. J. W. Roughton, Proc. Roy. Soc. (London), Ser. A, 104, 376 (1923)
5. B. Chance, Photosyhthesis Research 80, 387 (2004), and references therein.
6. a) M. Eigen, Discuss. Faraday Soc. 17, 194 (1954) b) R. G. W. Norrish, G. Porter, Nature 164, 658 (1949)
7. a) C. V. Shank, E. P. Ippen, Appl. Phys. Lett. 24, 373 (1974) b) R. L. Fork, C. H. Brito Cruz, P. C. Becker, C. V. Shank, Opt. Lett. 12, 483 (1987)
8. D. E. Spence, P. N. Kean, W. Sibbett, Opt. Lett. 16, 42 (1991)
9. a) D. R. Herschbach, Angew. Chem., Int. Ed. Engl. 26, 1221 (1987) and references therein. b) Y. T. Lee, Science 236, 793 (1987) and references there in.
10. a) J. C. Polanyi, Faraday Discuss. Chem. Soc. 67, 129 (1979) b) J. C. Polanyi, Science 236, 680 (1987) and references therein.
11. A. H. Zewail, Femtochemistry - Ultrafast Dynamics of the Chemical Bond, Vols. I and II, World Scientific, New Jersey, Singapore (1994) and references therein.
12. W. C. Wiley, I. H. McLaren, Rev. Sci. Instrum. 26, 1150 (1955)
13. a) R. N. Zare and D. R. Herschbach, Proc. IEEE 51, 173 (1963) b) R. N. Zare, Mol. Photochem. 4, 1 (1972)
14. MicroMath® Scientist® for WindowsTM, Version 2.01, Copyright(c) 1986-1995, MicroMath, Inc.
15. W. H. Press, B. P. Flannery, S. A. Teukolsky, W. T. Vetterling, Numerical Recipes (Cambridge University Press, New York, 1992)
16. D.A. Hansen, E.K.C. Lee, J. Chem. Phys. 62, 183 (1975)
17. J. Heicklen, J. Am. Chem. Soc. 81, 3863 (1959)
18. E.K.C. Lee and R.S. Lewis, Adv. Photochem. 12, 1 (1980)
19. a) O. Anner, H. Zuckermann, Y. Haas, J. Phys. Chem. 89, 1336 (1985) b) H. Zuckermann, B. Schmits, Y. Haas, J. Phys. Chem. 92, 4835 (1988) c) H. Zuckermann, B. Schmits, Y. Haas, Chem. Phys. Lett. 151, 323 (1988) d) H. Zuckermann, B. Schmits, Y. Haas, J. Phys. Chem. 93, 4083 (1989) e) Y. Hass, Spectrochim. Acta A 46, 541 (1990)
20. NIST Chemistry WebBook (http://webbook.nist.gov/chemistry/)
21. S. W. North, D. A. Blank, J. D. Gezelter, C. A. Longfellow, Y. T. Lee, J. Chem. Phys. 102, 4447 (1995)
22. G. Hancock and K. R. Wilson, in Proceedings of the IVth International Symposium on Molecular Beams, Cannes, France, 1973.
23. K. W. Watkins and W. M. Word, Int. J. Chem. Kinet. 6, 855 (1974)
24. J. G. Philis and L. Goodman, J. Chem. Phys. 98, 3795 (1993)
25. P. D. Lightfoot, S. P. Kirwan, M. J. Pilling, J. Phys. Chem. 92, 4938 (1988)
26. M. Baba, H. Shinohara, N. Nishi, N. Hirota, Chem. Phys. 83, 221 (1984)
27. D. J. Donaldson and S. R. Leone, J. Chem. Phys. 85, 817 (1986)
28. E. L. Woodbridge, T. R. Fletcher, S. R. Leone, J. Phys. Chem. 92, 5387 (1988)
29. K. A. Trentelman, S. H. Kable, D. B. Moss, P. L. Houston, J. Chem. Phys. 91, 7498 (1989)
30. G. E. Hall, H. W. Metzler, J. T. Muckerman, J. M. Preses, R. E. Weston, Jr., J. Chem. Phys. 102, 6660 (1995)
31. a) J. C. Owrutsky, A. P. Baronavski, J. Chem. Phys. 108, 6652 (1998) b) J. C. Owrutsky, A. P. Baronavski, J. Chem. Phys. 110, 11206 (1999)
32. Q. Zhong, L. Poth, A. W. Castleman, Jr., J. Chem. Phys. 110, 192 (1999)
33. a) E. W. G. Diau, C. Kotting, A. H. Zewail, Chem. Phys. Chem. 2, 273 (2001) b) E. W. G. Diau, C. Kotting, A. H. Zewail, Chem. Phys. Chem. 2, 294 (2001) c) E. W. G. Diau, C. Kotting, T. I. Solling, A. H. Zewail, Chem. Phys. Chem. 3, 57 (2002) d) T. I. Solling, E. W. G. Diau, C. Kotting, S. De Feyter, A. H. Zewail, Chem. Phys. Chem. 3, 79 (2002)
34. G. A. Gaines, D. J. Donaldson, S. J. Strickler, V. Vaida, J. Phys. Chem. 92, 2762 (1988)
35. P. Brint, L. O’Toole, S. Couris, D. Jardine, J. Chem. Soc., Faraday Trans. 87, 2891 (1991)
36. G. M. Breuer, E. K. C. Lee, J. Phys. Chem. 75, 989 (1971)
37. F. Ossler, M. Alden, Appl. Phys. B 64, 493 (1997)
38. T. Shibata, T. Suzuki, Chem. Phys. Lett. 262, 115 (1996)
39. S. W. North, D. A. Blank, Y. T. Lee, Chem. Phys. Lett. 224, 38 (1994)
40. M. Ito, S. Nanbu, M. Aoyagi, Institute for Molecular Sciences Annual Review VIII-A-3, 176 (1998)
41. A. Peña~Gallego, E. Martínez-Núñez, S. A. Vázquez, J. Chem. Phys. 110, 11323 (1999)
42. R. J. Campbell,E. W. Schlag, J. Am. Chem. Soc. 89, 5103 (1967)
43. E. Martínez-Núñez, A. Fernández-Ramos, M. N. D. S. Cordeiro, S. A. Vazquez, F. J. Aoiz, L. Bañares, J. Chem. Phys. 119, 10618 (2003)
44. D. H. Mordaunt, D. L. Osborn, D. M. Neumark, J. Chem. Phys. 108, 2448 (1998)
45. P. M. Kroger, S. J. Riley, J. Chem. Phys. 67, 4483 (1977)
46. R.-H. Li, J.-C. Wu, J.-L. Chang, Y.-T. Chen, Chem. Phys. 274, 275, (2001)
47. M. Baba, I. Hanazaki, U. Nagashima, J. Chem. Phys. 82, 3938 (1985)
48. D. L. Osborn, H. Choi, D. H. Mordaunt, R. T. Bise, D. M. Neumark, C. M. Rohlfing, J. Chem. Phys. 106, 3049 (1997)
49. J. T. Niiranen, D. Gutman, L. N. Krasnoperov, J. Phys. Chem. 96, 5881 (1992)
50. T. Bare, W. L. Hase, Unimolecular Reaction Dynamics：Theory and Experiment, Oxford University Press, Inc. (1996)
51. a) H. B. Singh, M. Kanakidou, P. J. Crutzen, D. J. Jacob, Nature 378, 50 (1995) b) T. Gierczak, J. B. Burkholder, S. Bauerle, A. R. Ravishankara, Chem. Phys. 231, 229 (1998) c) G. Vasvari, I. Szilagyi, A. Bencsura, S. Dobe, T. Berces, E. Henon, S. Canneaux, F. Bohr, Phys.Chem.Chem.Phys. 3, 551 (2001)
52. M. H. M. Janssen, M. Dantus, H. Guo, A. H. Zewail, Chem. Phys. Lett. 214, 281 (1993)
53. M. R. Dobber, W. J. Buma, C. A. de Lange, J. Phys. Chem. 99, 1671 (1995)
54. A. P. Baronavski, J. C. Owrutsky, J. Chem. Phys. 108, 3445 (1998)
55. K. Gollnick and H. Stracke, Pure. Appl. Chem. 33, 217 (1973)
56. X. Chen, H. Wang, B. R. Weiner, M. Hawley, H. H. Nelson, J. Phys. Chem. 97, 12269 (1993)
57. H. Q. Zhao, Y. S. Cheung, D. P. Heck, C. Y. Ng, T. Tetzlaff, W. S. Jenks, J. Chem. Phys. 106, 86 (1997)
58. D. A. Blank, S. W. North, D. Stranges, A. G. Suits, Y. T. Lee, J. Chem. Phys. 106, 539 (1997)
59. R. N. Rudolph, S. W. North, G. E. Hall, T. J. Sears, J. Chem. Phys. 106, 1346 (1997)
60. G. M. Thorson, C. M. Cheatum, M. J. Coffey, F. F. Crim, J. Chem. Phys. 110, 10843 (1999)
61. G. A. Amaral, I. Torres, G. A. Pino, F. J. Aoiz, L. Bañares, Chem. Phys. Lett. 386, 419 (2004)
62. G. A. Pino, I. Torres, G. A. Amaral, F. J. Aoiz, L. Bañares, J. Phys. Chem. A 108, 8048 (2004)
63. The heats of formation were taken from: CRC Handbook of Physics and Chemistry; CRC: Cleveland, 1985. S. G. Lias, J. E. Bartmess, J. F. Liebman, J. L. Holmes, R. D. Levine, W. G. Mallard, Phys. Chem. Ref. Data 17, (1988). S. W. Benson, Chem. Rev. 78, 23 (1978)
64. NIST Chemistry WebBook, http://webbook.nist.gov/chemistry/
65. J. W. Cubbage, W. S. Jenks, J. Phys. Chem. A 105, 10588 (2001)
66. X. Chen, F. Asmar, H. Wang, B. R. Weiner, J. Phys. Chem. 95, 6415 (1991)
67. T. K. Minton, P. Felder, R. J. Brudzynski, Y T. Lee, J. Chem. Phys. 81, 1759 (1984); S. W. North, D. A. Blank, Y. T. Lee, Chem. Phys. Lett. 222, 38 (1994)
68. E. W. G. Diau, C. Kotting, T. I. Solling, A. H. Zewail, Chem. Phys. Chem. 3, 57 (2002)
69. A. T. J. B. Eppink and D. H. Parker, J. Chem. Phys. 110, 832 (1999)
70. D. Zhong, P. Y. Cheng, A. H. Zawail, J. Chem. Phys. 105, 7864 (1996)