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The Weak Interaction on CO_2...CO van der Waals Complex: A Theoretical Study 被引量:1
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作者 CAO Zhao-hua +2 位作者 bu Yu-xiang 《Chemical Research in Chinese Universities》 SCIE CAS CSCD 2003年第1期94-99,共6页
The geometries of van der Waals complex CO 2...CO were optimized at DFT and second order Moller Plesset perturbation(MP2) levels with the large basis set, three stable structures were found. The most stable structu... The geometries of van der Waals complex CO 2...CO were optimized at DFT and second order Moller Plesset perturbation(MP2) levels with the large basis set, three stable structures were found. The most stable structure has a T shape geometry in which the CO lies along the C 2 axis of CO 2, with the two C atoms direct contact and R (C...C)=0 3227 nm. The corresponding energies of the most stable structure were calculated by means of MP2, MP4D, MP4DQ, MP4SDTQ, MP4SDQ, CCSD and CCSD(T) methods. The BSSE(basis set superposition error) was eliminated by the Boys Bernardi counterpoise correction(CP) method. According to thermodynamics data, van der Waals complex CO 2...CO can be found at a low temperature and/or a high pressure. There is a little charge transferred between the two interacted subunits. In the most stable structure, CO 2 is the acceptor and CO is the donor. 展开更多
关键词 CO 2...CO van der Waals complex Weak interaction MP2 calculation DFT calculation
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基于甲胺客体调制的混价态甲酸铁框架的构筑与磁电行为研究 被引量:3
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作者 赵炯鹏 王玮玮 +4 位作者 韩松德 李泉文 李娜 刘福臣 卜显和 《化学学报》 SCIE CAS CSCD 北大核心 2020年第11期1223-1228,共6页
N-型亚铁磁体可以在场冷时呈现负磁化行为,但在1 T强场场冷时依然能够保持负磁化行为的化合物却很罕见.本工作以CH3NH3+为客体阳离子,成功构筑了一例红砷镍矿(49.66)(412.63)结构的混价态甲酸铁化合物[CH3NH3]n[FeIIIFeII(HCO2)6]n(1),... N-型亚铁磁体可以在场冷时呈现负磁化行为,但在1 T强场场冷时依然能够保持负磁化行为的化合物却很罕见.本工作以CH3NH3+为客体阳离子,成功构筑了一例红砷镍矿(49.66)(412.63)结构的混价态甲酸铁化合物[CH3NH3]n[FeIIIFeII(HCO2)6]n(1),在1 T强场下呈现负磁化行为.1中甲酸根采用反,反模式连接FeII和FeIII形成三维阴离子框架,八面体配位构型的FeII和FeIII分别处于(49.66)和(412.63)节点,而CH3NH3+则填充在框架空隙中平衡电荷.量热、介电和单晶X-射线衍射测试结果表明,1中存在由CH3NH3+无序-有序转变诱导的结构相变并伴随介电弛豫.磁性研究表明FeII和FeIII之间存在较强的反铁磁耦合,但在冷却过程中FeII和FeIII构成的亚晶格磁有序程度存在较大差异,且具有较小自旋的FeII磁矩先于FeIII磁矩有序且平行于外加磁场,导致温度进一步降低时1呈现出负磁化行为,这表明1是一例罕见的N-型亚铁磁体.此外,1在1 T外加冷却场中依然能保持负磁化行为,表明1中存在较强的磁各向异性.值得注意的是,在100 Oe外场下冷却到17 K后,1呈现出正场调制的磁极翻转行为.进一步研究表明,1的场冷磁滞回线呈现不对称形状,并向冷却场方向发生偏转,其有效矫顽力(HC eff=(H+-H-)/2)和交换偏置场(HEB=(H++H-)/2)分别为21716 Oe和3322 Oe.总之,本研究表明客体分子尺寸和形状能够有效调控红砷镍矿结构中FeII的磁各向异性,从而实现较高的磁极翻转场、矫顽力和交换偏置场. 展开更多
关键词 混价态 相变 负磁化 磁极翻转 交换偏置
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