方维海
分子光解离反应机理,尤其在势能面交叉点的优化方法和应用于具体的光化学反应中,取得了新的研究成果
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- 姓名:方维海
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学术头衔:
博士生导师, 优秀教师/优秀教育工作者
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学科领域:
物理化学
- 研究兴趣:分子光解离反应机理,尤其在势能面交叉点的优化方法和应用于具体的光化学反应中,取得了新的研究成果
方维海, 男, 北京师范大学化学系教授。1990年9月--1993年6月在北京师范大学化学系, 攻读博士学位。1993年9月--1995年9在南京大学做博士后工作。1996年5月--1998年8在德国波恩大学理论化学所,洪堡学者。1998年8月至今,在北京师范大学工作。现为博士生导师。从1990年攻读博士学位开始,就开展了光化学反应的理论研究。曾巧妙地改编和应用GVB方法程序,进行限制性的开壳层Hartree-Fock计算。曾将有效单电子旋轨偶合算符和分子中原子近似方法相结合,在从头算MR-CI水平上,研究自旋禁阻的热解和光解反应。在绝热和非绝热反应速率理论方面做了大量的研究。近年来主要研究领域是分子光解离反应机理,尤其在势能面交叉点的优化方法和应用于具体的光化学反应中,取得了新的研究成果。自1998年以来,平均每年以第一或联系作者在J. Am. Chem. Soc.上发表一篇相关论文。同时有大量光化学反应方面的研究工作在J. Chem. Phys., J. Phys. Chem.和 J. Org. Chem.等国际一流刊物上发表。从1995到2003年底,论文共被他人引用285次。多次应邀在国际会议上作邀请报告。2003年被教育部评为全国高等学校优秀骨干教师。作为第一完成人,2003年获得教育部科学技术一等奖。光化学反应机理方面研究工作,在国际上该领域有一定的影响。
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【期刊论文】An ab Initio Study toward Understanding the Mechanistic Photochemistry of Acetamide
方维海, Xue-Bo Chen, Wei-Hai Fang, * and De-Cai Fang*
J. AM. CHEM. SOC. 2003, 125, 9689-9698,-0001,():
-1年11月30日
The potential energy surfaces for CH3CONH2 dissociation into CH3 + CONH2, CH3CO + NH2, CH3CN + H2O, and CH3NH2 + CO in the ground and lowest triplet states have been mapped with DFT, MP2, and CASSCF methods with the cc-pVDZ and cc-pVTZ basis sets, while the S1 potential energy surfaces for these reactions were determined by the CASSCF/cc-pVDZ optimizations followed by CASSCF/MRSDCI single-point calculations. The reaction pathways leading to different photoproducts are characterized on the basis of the computed potential energy surfaces and surface crossing points. A comparison of the reactivity among HCONH2, CH3CONH2, and CH3CONHCH3 has been made, which provides some new insights into the mechanism of the ultraviolet photodissociation of small amides.
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方维海, Wei-Hai Fang a)
VOLUME 112, NUMBER 3, 2000 112 (3): 1204-1211,-0001,():
-1年11月30日
The structures and properties of phenol and its complex were characterized at the Hartree-Fock (HF), the second-order Moller-Plesset perturbation theory (MP2), and complete active space self-consistent field (CASSCF) levels for the ground state (S0) and at the configuration interaction with single excitation (CIS) and CASSCF levels for the excited electronic state (S1). The intermolecular interaction has little influence on the structures of phenol and water. However, a significant change is found in the properties upon complex, and this has been discussed in detail. A comparison with the experimental findings shows that the present calculations provide a good description of the nature of phenol and its complex in S0 and S1.
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方维海, Wei-Hai Fang
VOLUME 111, NUMBER 12, 1999 111 (22): 5361-5367,-0001,():
-1年11月30日
The structures and properties of indole and its complexes in S0 and S1 were characterized with the Hartree-Fock (HF), configuration interaction with single excitation (CIS), and complete active space self-consistent field (CASSCF) methods, using the 3-21G and 6-31G* basis sets. The influence of the intermolecular interaction on the structures and properties of the complexes was discussed in detail. A comparison is made between the results reported here and those from previous theoretical and experimental studies.
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方维海, Wei-Hai Fang a) and Ruo-Zhuang Liu b)
VOLUME 115, NUMBER 12, 2001 115 (21): 5411-5417,-0001,():
-1年11月30日
Potential energy surfaces of the HFCO dissociation to H1FCO and F1HCO in the lowest three electronic states (S0, S1, and T1) have been investigated with ab initio molecular orbital method at the level of the complete active space self-consistent field. An insight into the dynamics of the HFCO photodissociation at the range of 193-248nm was provided in the present work. Radiationless transfer from S1 to T1 and subsequent dissociation on the T1 surface was predicted to be the mechanism for the C-H bond cleavage, which is consistent with that proposed by experimentalists. The experimental investigations of the HFCO photodissociation suggest that the F-C bond fission also occurs as a result of intersystem crossing (ISC) from S1 to T1, which is not supported by the present calculations. This has been discussed in detail.
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方维海, Hong-Yuan He and Wei-Hai Fang*
J. AM. CHEM. SOC. 2003, 125, 16139-16147,-0001,():
-1年11月30日
The S0, T1, and S1 potential energy surfaces for the HCOOH dissociation and isomerization processes have been mapped with different ab initio methods. The wavelength-dependent mechanism for the HCOOH dissociation was elucidated through the computed potential energy surfaces and the surface crossing points. The HCOOH molecules in S1 by excitation at 248nm mainly decay to the ground state via the S0 and S1 vibronic interaction, followed by molecular eliminations in the ground state. The S1 direct dissociation to HCO(2A
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方维海, David Lee Phillips, *, † Wei-Hai Fang, ‡ and Xuming Zheng†
J. Am. Chem. Soc. 2001, 123, 4197-4203,-0001,():
-1年11月30日
We examine the chemical reactions of the isodiiodomethane (CH2I-I), âCH2I and CH2I+ species with ethylene using density functional theory computations. The CH2I-I species readily reacts with ethylene to give the cyclopropane product and an I2 product via a one-step reaction with a barrier height of ~2.9 kcal/mol. However, the âCH2I and CH2I+ species have much more difficult pathways (with larger potential barriers) to react with ethylene via a two-step reaction mechanism. Comparison of experimental results to our present calculation results indicates that the CH2I-I photoproduct species is most likely the methylene transfer agent for the cyclopropanation reaction of olefins via ultraviolet photoexcitation of diiodomethane.
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方维海, Wei-Hai Fang*, Dong-qi Wang, and Yun-Liang Li
J. Org. Chem. 2002, 67, 154-160,-0001,():
-1年11月30日
The insertion reaction of zinc into the C-I bond of CH2I2 and subsequent cyclopropanation reactions with CH2CH2 have been investigated using B3LYP level density functional theory calculations. The Simmons-Smith cyclopropanation reaction of olefins does not proceed easily due to the relatively large barriers on the insertion and cyclopropanation pathways. The computed results indicate that the IZnCH2I molecule is the active reagent in the Simmons-Smith reaction. This is consistent with the IZnCH2I reactive species being generated from diiodomethane and a Zn-Cu couple as proposed by several other research groups. The Simmons-Smith IZnCH2I carbenoid and CH2I-I carbenoid cyclopropanation reactions with olefins are compared. The reactions of olefins with the radicals from the decomposition of the IZnCH2I and CH2I-I species were also compared. We found that the chemical reactivity of the carbenoid species is dependent on its electrophilic behavior, steric effects, the leaving group character and the mechanism of the cyclopropanation reactions.
David Lee Phillips,, *, Department of Chemistry,, University of Hong Kong,, Pokfulam Road,, Hong Kong,, P., R., China
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【期刊论文】Photodissociation of Acrylic Acid in the Gas Phase: An ab Initio Study
方维海, Wei-Hai Fang* and Ruo-Zhuang Liu
J. Am. Chem. Soc. 2000, 122, 10886-10894,-0001,():
-1年11月30日
The potential energy profiles, governing the dissociation of acrylic acid (CH2CHCOOH) to CH3CH + CO2, CH2CHOH + CO, CH2CH + COOH and CH2CHCO + OH in the ground as well as in the excited singlet and triplet states, have been determined using different ab initio quantum chemical methods with a correlation-consistent atomic natural orbital basis set of cc-pVDZ. The most probable mechanism leading to different products is characterized on the basis of the obtained potential energy surfaces of the dissociation and the crossing points of the surfaces.
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【期刊论文】A CASSCF Study on Photodissociation of Acrolein in the Gas Phase
方维海, Wei-Hai Fang*
J. Am. Chem. Soc. 1999, 121, 8376-8384,-0001,():
-1年11月30日
The potential energy profiles, governing the dissociation of CH2CHCHO to CH3CH + CO, CH2CH + CHO, and CH2CHCO + H in the ground state as well as in the excited singlet and triplet states, have been determined using different ab initio quantum mechanical methods with a correlation-consistent atomic natural orbital basis set, cc-pVDZ. The most probable mechanism leading to different products is characterized on the basis of the obtained potential energy profiles and their crossing points. Also, the geometric and electronic structures of some low-lying electronic states of acrolein, methylketene, methylcarbene, and the CH2CHCO radical are determined by the CASSCF computations.
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方维海, Wei-Hai Fang†
J. Am. Chem. Soc. 1998, 120, 7568-7576,-0001,():
-1年11月30日
The triple-proton-transfer reactions in the ground and first excited states of 7-hydroxyquinoline (7HQ) in methanol solution have been investigated by employing different ab initio quantum mechanical methods. The solvent effects on the structures and potential energy profiles of the reactions were included with the use of the Onsager self-consistent reaction field model. The potential energy profiles governing multiproton transfers were optimized at the HF and MP2 levels for the ground state and at the CIS and CASSCF levels for the first excited state. A conclusive description of the photoinduced proton-transfer cycle is given on the basis of the calculated potential energy profiles and transition energies, together with the experimental findings. The main features of the absorption and emission spectra concerning the ground and the first excited states of 7HQ were elucidated by analyzing the CIS and CASSCF calculated results. Electron correlation plays an important role in the description of the geometric features of 7HQ and the proton-transfer reactions in the complex, and this has been discussed in detail.
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