Structural and magnetic properties are investigated for Fe1-xMnxV2O4 （0≤ x ≤ 1） spinels. As orbital-active Fe^2＋ is substituted with Mn^2＋, the cubie-to-tetragonM transition TsI and the tetragonal-to-orthorhombi...Structural and magnetic properties are investigated for Fe1-xMnxV2O4 （0≤ x ≤ 1） spinels. As orbital-active Fe^2＋ is substituted with Mn^2＋, the cubie-to-tetragonM transition TsI and the tetragonal-to-orthorhombic transition Ts2 gradually decrease. These structural transitions originate from the Fe^2＋ ferro-orbital order （F-OO）. Below Yafet-Kittel （YK） magnetic transition TN2, V^3＋ orbital order （V-OO） plays an important role on global structure. Here x = 0.6 is a critical point. Fe^2＋ F-OO and V^3＋ F-OO coexist for 0 ≤ x ≤ 0.5. For x≥ 0.6, the orbital pattern of V^3＋ is antiferro （AF）-00, and Fe^2＋ F-OO disappears. Structural transition Ts3, accompanied by YK magnetic transition TN2, decreases initially, and then increases at x = 0.6. A scenario for the complex phase diagram arising from the cooperation or competition of Fe^2＋ and V^3＋ orbitals is proposed.展开更多
Tetrazole monomers （Ⅰ, Ⅱ） and all of their possible stable dimers （1, 2, 3, 4, 5, 6, 7 and 8） were fully optimized by DFT method at the B3LYP/6-311＋＋G^＊＊ level. Among the eight dimers, there were two 1H-tetr...Tetrazole monomers （Ⅰ, Ⅱ） and all of their possible stable dimers （1, 2, 3, 4, 5, 6, 7 and 8） were fully optimized by DFT method at the B3LYP/6-311＋＋G^＊＊ level. Among the eight dimers, there were two 1H-tetrazole dimers, three 2H-tetrazole dimers and three hetero dimers of 1H-tetrazole and 2H-tetrazole. Vibrational frequencies were calculated to ascertain that each structure was stable （no imaginary frequencies）. The basis set superposition errors （BSSE） are 2.78, 2.28, 2.97, 2.75, 2.74, 2.18, 1.23 and 3.10 kJ/mol, and the zero point energy （ZPE） corrections for the interaction energies are 4.88, 4.18, 3.87, 3.65, 3.54, 3.22, 2.87 and 4.34 kJ/mol for 1, 2, 3, 4, 5, 6, 7 and 8, respectively. After BSSE and ZPE corrections, the greatest corrected intermolecular interaction energy of the dimers is -43.71 kJ/mol. The charge redistribution mainly occurs on the adjacent N-H…N atoms between submolecules. The charge transfer between two subsystems is very small. Natural bond orbital （NBO） analysis was performed to reveal the origin of the interaction. Based on the statistical thermodynamic method, the standard thermodynamic functions, heat capacities （C^0P）, entropies （S^0T） and thermal corrections to enthalpy （H^0T）, and the changes of thermodynamic properties from monomer to dimer in the temperature range of 200.00 K to 700 K have been obtained. 1H-tetrazole monomer can spontaneously turn into two stable dimers at 298.15 K.展开更多
We introduce the concept of asymptotic pseudo orbit tracing property (APOTP) and obtain a new condition by the APOTP for which a homeomor-phism is a non-wandering homeomorphism.
基金Supported by the National Basic Research Program of China under Grant Nos 2011CB921904 and 2012CB927402the National Natural Science Foundation of China under Grant Nos 11074142 and 11021464+1 种基金the Key Project of Chinese Ministry of Education under Grant No 309003the Tsinghua TNList Cross-discipline Foundation
文摘Structural and magnetic properties are investigated for Fe1-xMnxV2O4 （0≤ x ≤ 1） spinels. As orbital-active Fe^2＋ is substituted with Mn^2＋, the cubie-to-tetragonM transition TsI and the tetragonal-to-orthorhombic transition Ts2 gradually decrease. These structural transitions originate from the Fe^2＋ ferro-orbital order （F-OO）. Below Yafet-Kittel （YK） magnetic transition TN2, V^3＋ orbital order （V-OO） plays an important role on global structure. Here x = 0.6 is a critical point. Fe^2＋ F-OO and V^3＋ F-OO coexist for 0 ≤ x ≤ 0.5. For x≥ 0.6, the orbital pattern of V^3＋ is antiferro （AF）-00, and Fe^2＋ F-OO disappears. Structural transition Ts3, accompanied by YK magnetic transition TN2, decreases initially, and then increases at x = 0.6. A scenario for the complex phase diagram arising from the cooperation or competition of Fe^2＋ and V^3＋ orbitals is proposed.
文摘Tetrazole monomers （Ⅰ, Ⅱ） and all of their possible stable dimers （1, 2, 3, 4, 5, 6, 7 and 8） were fully optimized by DFT method at the B3LYP/6-311＋＋G^＊＊ level. Among the eight dimers, there were two 1H-tetrazole dimers, three 2H-tetrazole dimers and three hetero dimers of 1H-tetrazole and 2H-tetrazole. Vibrational frequencies were calculated to ascertain that each structure was stable （no imaginary frequencies）. The basis set superposition errors （BSSE） are 2.78, 2.28, 2.97, 2.75, 2.74, 2.18, 1.23 and 3.10 kJ/mol, and the zero point energy （ZPE） corrections for the interaction energies are 4.88, 4.18, 3.87, 3.65, 3.54, 3.22, 2.87 and 4.34 kJ/mol for 1, 2, 3, 4, 5, 6, 7 and 8, respectively. After BSSE and ZPE corrections, the greatest corrected intermolecular interaction energy of the dimers is -43.71 kJ/mol. The charge redistribution mainly occurs on the adjacent N-H…N atoms between submolecules. The charge transfer between two subsystems is very small. Natural bond orbital （NBO） analysis was performed to reveal the origin of the interaction. Based on the statistical thermodynamic method, the standard thermodynamic functions, heat capacities （C^0P）, entropies （S^0T） and thermal corrections to enthalpy （H^0T）, and the changes of thermodynamic properties from monomer to dimer in the temperature range of 200.00 K to 700 K have been obtained. 1H-tetrazole monomer can spontaneously turn into two stable dimers at 298.15 K.
基金Project supported by the National Natural Science Foundation of China(10361001)the Natural Science Foundation of the Committee of Education of Jiangshu Province (02KJB110008).
文摘We introduce the concept of asymptotic pseudo orbit tracing property (APOTP) and obtain a new condition by the APOTP for which a homeomor-phism is a non-wandering homeomorphism.
