資源描述：
《銅鎂鋁三元水滑石的姜-泰勒效應(yīng)》由會(huì)員上傳分享，免費(fèi)在線閱讀，更多相關(guān)內(nèi)容在行業(yè)資料-天天文庫(kù)。
1、物理化學(xué)學(xué)報(bào)(WuliHuaxueXuebao)2088ActaPhys.-Chim.Sin.2011,27(9),2088-2094September[Article]www.whxb.pku.edu.cn銅鎂鋁三元水滑石的姜-泰勒效應(yīng)*劉嬌姚萍倪哲明李遠(yuǎn)施煒(浙江工業(yè)大學(xué)化學(xué)工程與材料學(xué)院,先進(jìn)催化材料實(shí)驗(yàn)室,杭州310032)摘要:采用密度泛函理論(DFT),用CASTEP程序模塊,對(duì)類水滑石(CuxMg3-xAl-LDHs,x=0-3)周期性模型進(jìn)行幾何全優(yōu)化,通過(guò)分析各體系的結(jié)構(gòu)參數(shù)、電子排布、氫鍵、Mulliken電荷布居、結(jié)合能,總結(jié)出體系中的姜-泰勒效應(yīng)和結(jié)構(gòu)穩(wěn)定性
2、規(guī)律.結(jié)果表明,姜-泰勒效應(yīng)不僅存在于d軌道未排滿的Cu2+中,在p軌道未排滿的Mg2+中也可能存在,且未飽和的d、p軌道共同影響著金屬離子姜-泰勒畸變的大小.在CuxMg3-xAl-LDHs(x=0-3)中,鋁八面體和鎂八面體分別以穩(wěn)定的拉長(zhǎng)的八面體形式存在.而隨著Cu2+的增加,銅八面體逐漸從壓扁的八面體向穩(wěn)定的拉長(zhǎng)的八面體形式轉(zhuǎn)變,體系獲得了逐漸增多的姜-泰勒穩(wěn)定化能.總體上,隨著Cu2+的增加,體系中姜-泰勒效應(yīng)導(dǎo)致的畸變使主客體間的氫鍵和靜電作用力均有減弱趨勢(shì),且體系的結(jié)合能絕對(duì)值逐漸減小,故體系穩(wěn)定性下降.這有助于從理論上進(jìn)一步認(rèn)識(shí)含銅水滑石的姜-泰勒效應(yīng).關(guān)鍵詞:水滑
3、石;姜-泰勒效應(yīng);密度泛函理論;結(jié)合能;Mulliken布居中圖分類號(hào):O641Jahn-TellerEffectofCu-Mg-AlLayeredDoubleHydroxides*LIUJiaoYAOPingNIZhe-MingLIYuanSHIWei(LaboratoryofAdvancedCatalyticMaterials,CollegeofChemicalEngineeringandMaterialsScience,ZhejiangUniversityofTechnology,Hangzhou310032,P.R.China)Abstract:Weproposeaperi
4、odicinteractionmodelforthelayereddoublehydroxides,CuxMg3-xAl-LDHs(x=0-3).Basedondensityfunctionaltheory,thegeometriesofCuxMg3-xAl-LDHs(x=0-3)wereoptimizedusingtheCASTEPprogram.TheJahn-Tellereffectandthestabilitywereinvestigatedbyanalyzingthegeometricparameters,electronicarrangement,hydrogen-bo
5、nding,chargepopulations,andbindingenergies.TheresultsshowthattheJahn-TellereffectexistsintheunfilledCu2+dorbitalandalsoexistsintheunfilledMg2+porbital.ThetwoorbitalsaffecttheJahn-Tellerdistortionofthemetalions.InCuxMg3-xAl-LDHs(x=0-3),bothaluminumandmagnesiumexistinstabilizedoctahedralforms.Wi
6、thanincreaseofCu2+inthelayertheoctahedralofcopperchangesfromaflatconfigurationtoastableelongatedconfigurationandtheJahn-Tellerstabilizationenergyofthesystemgraduallyincreases.Ingeneral,withanincreaseofCu2+inthelayerthedistortioncausedbytheJahn-Tellereffectweakenshydrogen-bondingandtheelectrost
7、aticinteractionsbetweenthehostlayerandtheguest.Theabsolutevalueofthebindingenergydecreasesandthechemicalstabilityofthesystemdecreasesaswell.ThisallowsustotheoreticallyunderstandtheJahn-Tellereffectbetterforthesynthesisofcopper-containin
