High-frequency time-resolved EPR Study on the Short-lived Paramagnetic Species

短寿命顺磁性物质的高频时间分辨 EPR 研究

• 批准号: 07404040
• 负责人: TERO Shozo
• 金额: $ 19.33万
• 依托单位: TOHOKU UNIVERSITY
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (A)
• 财政年份: 1995
• 资助国家: 日本
• 起止时间: 1995 至 1997
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-07404040/
• 关键词: time-resolved spectroscopy; spin dynamics; short-lived species; radical pairs; excited triplet states; spin-orbit interaction; exhange interaction; carbene; 短寿命常時性種

We built a Q-band time-resolved EPR spectrometer, which works with a pulsed laser. We applied the system to verify the mechanism of the ClDEP spectra due to short-lived radicals and the broadening mechanism of the time-resolved EPR spectra due to short-lived excited triplet states.1. Microwave frequency dependence of spin-polarized EPR spectra(a) The CIDEP spectra involving triplet mechanism depends on significantly to the observed frequency.(b) Time-resolved EPR measurements on the excited triplet states verified that the spectral broadening due to the g-anisotropy is clearly distinguished from the other mechanisms.2. The sign of the exchange interaction in the radical ion pairs.The present study verified that the exchange interaction is governed by charge transfer interaction rather than covalent bonding interactions, The level crossing between the potential surfaces of the radical ion pair state and ground state is a key factor.3. Electronic structure of the excited state of diphenyl carben.We successfully observed the short-lived excited state of diphenylmethylene and determined the zero-field splitting constants.4. Structure of the dangling bonds in microcrystalline silicon.Q-band EPR measurements verified the existence of three kinds of signals due to dangling bonds in microcrystalline silicon.5. Eelctronic structure of the excited triplet states having unusually large zero-field splitting constants.

我们建立了一个Q波段时间分辨EPR光谱仪，它与脉冲激光。我们应用该系统验证了短寿命自由基引起的ClDEP谱的机制和短寿命激发三重态引起的时间分辨EPR谱的展宽机制.自旋极化EPR谱的微波频率依赖性（a）涉及三重态机制的CIDEP谱显著依赖于观测频率。(b)对激发三重态的时间分辨EPR测量证实了g各向异性引起的光谱展宽与其他机制明显不同.自由基离子对中交换作用的标志，本研究证实了交换作用是由电荷转移作用而不是共价键作用控制的，自由基离子对态和基态的势能面之间的能级交叉是一个关键因素.二苯基碳烯激发态的电子结构成功地观察到了二苯基亚甲基的短寿命激发态，并测定了零场分裂常数.微晶硅中悬挂键的结构Q波段EPR测量证实了微晶硅中悬挂键产生的三种信号的存在.具有异常大的零场分裂常数的激发三重态的电子结构。

项目成果

S.Sasaki: "Spin-Orbit Coupling Induced Electron Spin Polarization: Influence of Heavy Atom Position" J.Am.Chem.Soc.119(6). 1323-1327 (1997)

S.Sasaki：“自旋轨道耦合引起的电子自旋极化：重原子位置的影响”J.Am.Chem.Soc.119(6)。

S.Sekiguchi: "Marcus Free Energy Dependence of the Sign of Exchange Interactions in Radical Ion Pairs Generated by Photoinduced Electron Transfer Reactions" J.Am.Chem.Soc.120(6). 1325-1325 (1998)

S.Sekiguchi：“光诱导电子转移反应产生的自由基离子对中交换相互作用符号的马库斯自由能依赖性”J.Am.Chem.Soc.120(6)。

T.Ikoma: "Twist Conformational Effects on the Excited Triplet States of Aromatic Ketones Studied by Multifrequency TREPR and pulsed EPR Spectroscopy" Mol.Phys.in press.

T.Ikoma：“通过多频 TREPR 和脉冲 EPR 光谱研究扭曲构象对芳香酮激发三重态的影响”Mol.Phys.in 出版社。

S.Sekiguchi: "Effects of Lewis Acid on the Sign of Exchange Interaction of Photogenerated Radical Ion Pairs" J.Chem.Soc.Perkin Trans.2. 1619-1620 (1997)

S.Sekiguchi：“路易斯酸对光生自由基离子对交换相互作用符号的影响”J.Chem.Soc.Perkin Trans.2。

T.Shimokage: "Substituent and Matrix Effects on the Excited Triplet States of 1,4-Naphthoquinones" J.Phys.Chem. 101(49). 9253-9256 (1997)

T.Shimokage：“取代基和基质对 1,4-萘醌激发三重态的影响”J.Phys.Chem。