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田中群, De-Yin Wu, *, †, Bin Ren, Yu-Xiong Jiang, Xin Xu, ‡, and Zhong-Qun Tian*
J. Phys. Chem. A 2002, 106, 9042-9052,-0001,():
-1年11月30日
Raman and infrared (IR) spectroscopies have been used extensively to study the adsorption of pyridine on various surfaces for more than 40 years. However, no satisfactory assignment on all the vibrational modes has been achieved. In the present study, density functional theory at the level of B3LYP/6-311+G** (for C, N, H)/LANL2DZ (for metals) has been used for the normal coordinate calculations of the neutral and cationic species of the pyridine-metal atom (ion) complexes. Based on the present calculations, new assignments of the fundamental frequencies for the bands attributed to V17a, V3, V5, and V18b modes of the free pyridine in the reported IR and Raman spectra have been suggested. The calculated frequency shifts indicate that the coupling among V1, V12, and V18a modes and the coupling between these modes and the N-metal (Cu, Ag, Au, or Pt) bond depend on the strength of the N-metal bond and its bonding properties. The fundamental frequency of the V6a mode has a nearly linear relationship with the change of the force constant of the N-M bond. Therefore, its frequency shift can be used to directly correlate to the strength of the interaction of pyridine with the metal atom (surface).
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【期刊论文】3.6 Raman Spectroscopy of Electrode Surfaces
田中群, Zhong-Qun Tian and Bin Ren
3 In-situ Structural and Spectroscopic Probes of Electrochemical Systems,-0001,():
-1年11月30日
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田中群, Zhong-Qun Tian, *, Bin Ren, and De-Yin Wu
VOLUME 106, NUMBER 37, SEPTEMBER 19, 2002,-0001,():
-1年11月30日
In the mid-1970s, surface-enhanced Raman scattering (SERS) was discovered which impacted on surface science and spectroscopy because of its extremely high surface sensitivity. However, SERS had not developed as many people had hoped to be a powerful surface diagnostic technique that can be widely used because of some obstacles. For example, only three noble metals Au, Ag, and Cu could provide large enhancement, severely limiting the widespread applications involving other metallic materials of both fundamental and practical importance. In this article, emphasis is put on the recent work of our group to directly generate SERS on net transition metals (e.g., Pt, Ru, Rh, Pd, Fe, Co, Ni, and their alloys) by developing various roughening procedures and optimizing the performance of the confocal Raman microscope. An approach of replacing the randomly roughened surface with ordered nanorod arrays of transition metals is introduced as a promising class of highly SERS-active substrates. The surface enhancement factor for transition metals was calculated, which ranged from 1 to 4 orders of magnitude. The applications of SERS in surface adsorption, electro-catalysis, and corrosion of transition-metal-based systems demonstrated several advantages of in situ surface Raman spectroscopy. A preliminary theoretical approach, considering the electromagnetic and chemical contributions, is presented to explain the SERS behavior of transition metal electrodes and nanorod arrays. It has been shown that SERS together with other surface-enhanced optical phenomena could be one of important issues not only in surface science but also in nanoscale science. Prospects and further developments in this exciting field are discussed with emphasis on the emerging experimental methodology.
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【期刊论文】A Simple and Effective Route for the Synthesis of Crystalline Silver Nanorods and Nanowires**
田中群, By Jian-Qiang Hu, Qing Chen, Zhao-Xiong Xie, Guo-Bin Han, Rui-Hong Wang, Bin Ren, Yong Zhang, Zhi-Lin Yang, and Zhong-Qun Tian*
Adv, Funct. Mater. 2004, 14, No.2, February,-0001,():
-1年11月30日
A simple and effective approach to the aqueous-phase synthesis of crystalline silver nanorods and nanowires is demonstrated, using which their diameters and aspect ratios can be effectively controlled. The synthesis involves a template-less and non-seed process to high-quality nanoparticles, which is low-cost and proceeds at moderate temperatures. The nanorods and nanowires were synthesized by the reduction of silver nitrate with tri-sodium citrate in the presence of sodium dodecylsulfonate. The concentration of tri-sodium citrate plays a critical role while sodium dodecylsulfonate, as a capping agent, only plays an assistant role in controlling the diameters and aspect ratios of the products. High-resolution transmission electron microscopy (HRTEM) and selected-area electron diffraction (SAED) investigations show that the silver nanocrystals are generated with a twinned crystalline structure. We also put forward a primary experimental model to shed light on their growth mechanisms.
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田中群, Z. Q. Tian, *, B. Ren, and B. W. Mao
J. Phys. Chem. B 1997, 101, 1338-1346,-0001,():
-1年11月30日
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