1997 Fiscal Year Final Research Report Summary
Study on optically forbidden excited states by photodetachment threshold electron spectroscopy
| Project/Area Number |
07454155
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Physical chemistry
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| Research Institution | Hiroshima City University |
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Principal Investigator |
ISHIWATA Takashi Hiroshima City University Faculty of Information Sciences Professor, 情報科学部, 教授 (40134811)
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| Co-Investigator(Kenkyū-buntansha) |
FUJIWARA Hisashi Hiroshima City University Faculty of Information Sciences Research Associate, 情報科学部, 助手 (40264949)
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| Project Period (FY) |
1995 – 1997
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| Keywords | Cl_2 / NO_3 / HOCl / Double resonace / Vibronic coupling / Photodisociation / Anisotropy |
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| Research Abstract |
There are the excited states which are optically forbidden to access from the ground state due to several restrictions, such as the symmetrical selection rules and the spin conservation. This study aimed to find these excited states by photodetachment threshold electron spectroscopy, and to elucidate their nature in combining with other spectroscopic techniques.
(1)Ion-pair states of molecular chlorine : The 0^+_(^3P_0) states inaccessible from the ground states due to the Franck-Condon restriction was identified by optical-optical double resonance through the B^3II(0^+_) state.The 0^-_(^3P_1) state was also accessed through the A^3II(1_u)-B'^3II(0^-_) interacting states by perturbation-facilitated optical double resonance. The potential functions of these excited states were determined.
(2)Electronically excited states of NO _3 radical : The molecular constants of the ^2A_2 ground stats are determined from the infrared absorption band using the combination differences.The symmetrically
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forbidden excited state (^2E") was found in the infrared region. using the Zeeman modulation, the specturm was assigned as the parallel transition to the ^2A"_1 vibronic state in which the e" vibration broke the Born-oppenheimer approximation through the vibronic interaction in the excited state.
(3)Electronically excited states of HOCl : When we photodissociate the HOCI radical which is important in the stratospheric ozone balance, the OH fragment showed its velocity to be aligned along the electronic vector of the photolysis light at 266 nm. The photoabsorption at this wavelength proceeds through 2^1A'-1^1A' transition whose transition moment is parallel to the O-Cl axis. On the other hand, in the photolysis at 355nm, the OH fragments were aligned perpendicular to the electronic vector of photolysis light, indicating that the 1^1A"-1^1A'transition occurred. Consequently, HOCl is photodissociated only through the singlet excited states, which is in contrast with the fact that the photodissociation can occur through a triplet state in the case of HOBr. Less
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