原子能科学技术
原子能科學技術
원자능과학기술
ATOMIC ENERGY SCIENCE AND TECHNOLOGY
2013年
11期
1925-1930
,共6页
伍冬兰%曾学锋%谭彬%谢安东
伍鼕蘭%曾學鋒%譚彬%謝安東
오동란%증학봉%담빈%사안동
密度泛函理论%硼氢化物%电子特性
密度汎函理論%硼氫化物%電子特性
밀도범함이론%붕경화물%전자특성
density functional theory%boron hydride%electronic characteristic
采用密度泛函(DFT )B3P86方法,结合Dunning 的相关一致三重基cc-pVTZ ,优化计算硼氢化物(B2 Hn )(n=1~6)可能的几何构型,得出最稳定结构的几何参数、电子结构和振动频率等参数,给出了最稳定结构的总能量(ET )、结合能(EBT )、平均结合能(Eav )、电离势(EIP )、能隙(Eg )、费米能级(EF )和氢原子差分吸附能( Edif )等。结果表明,硼氢化物基态稳定结构的电子态分别为:n为奇数时为双重态2 A ,n为偶数时为单重态1A。由于B原子属于缺电子原子,能与等电子原子 H化合,通过桥键形成多中心键的氢化物,优化计算发现,硼氢化物最稳定结构都存在桥键,且n为奇数的桥键作用比相邻偶数的强。通过分析最稳定结构的电子特性发现,B2 Hn (n=1~6)中B2 H6的电离势和能隙最大,桥键比端键长,红外光谱强度最大,说明该硼氢化物最稳定,且其氢原子差分吸附能最大,储氢性能相对最好。
採用密度汎函(DFT )B3P86方法,結閤Dunning 的相關一緻三重基cc-pVTZ ,優化計算硼氫化物(B2 Hn )(n=1~6)可能的幾何構型,得齣最穩定結構的幾何參數、電子結構和振動頻率等參數,給齣瞭最穩定結構的總能量(ET )、結閤能(EBT )、平均結閤能(Eav )、電離勢(EIP )、能隙(Eg )、費米能級(EF )和氫原子差分吸附能( Edif )等。結果錶明,硼氫化物基態穩定結構的電子態分彆為:n為奇數時為雙重態2 A ,n為偶數時為單重態1A。由于B原子屬于缺電子原子,能與等電子原子 H化閤,通過橋鍵形成多中心鍵的氫化物,優化計算髮現,硼氫化物最穩定結構都存在橋鍵,且n為奇數的橋鍵作用比相鄰偶數的彊。通過分析最穩定結構的電子特性髮現,B2 Hn (n=1~6)中B2 H6的電離勢和能隙最大,橋鍵比耑鍵長,紅外光譜彊度最大,說明該硼氫化物最穩定,且其氫原子差分吸附能最大,儲氫性能相對最好。
채용밀도범함(DFT )B3P86방법,결합Dunning 적상관일치삼중기cc-pVTZ ,우화계산붕경화물(B2 Hn )(n=1~6)가능적궤하구형,득출최은정결구적궤하삼수、전자결구화진동빈솔등삼수,급출료최은정결구적총능량(ET )、결합능(EBT )、평균결합능(Eav )、전리세(EIP )、능극(Eg )、비미능급(EF )화경원자차분흡부능( Edif )등。결과표명,붕경화물기태은정결구적전자태분별위:n위기수시위쌍중태2 A ,n위우수시위단중태1A。유우B원자속우결전자원자,능여등전자원자 H화합,통과교건형성다중심건적경화물,우화계산발현,붕경화물최은정결구도존재교건,차n위기수적교건작용비상린우수적강。통과분석최은정결구적전자특성발현,B2 Hn (n=1~6)중B2 H6적전리세화능극최대,교건비단건장,홍외광보강도최대,설명해붕경화물최은정,차기경원자차분흡부능최대,저경성능상대최호。
The possible geometrical structures of boron hydride (B2 Hn )(n=1-6) were optimized based on density functional theory of B3P86 method and the Dunning related consistent base group cc-pVTZ level .The configuration geometric parameter ,electronic structure and vibration frequency of the most stable structure were obtained ,and the total energy ( ET ) , binding energy ( EBT ) , average binding energy ( Eav ) , ionization potential (EIP ) , energy gap (Eg ) , Fermi level (EF ) , hydrogen atom differential adsorption energy (Edif ) and so on were given .The results show that the electronic states in ground state of boron hydride are 1 heavy condition w hen n is even number and they are 2 heavy condition w hen n is odd number ,respectively .In all boron hydrides , there is hydrogen bridge linkage .T hrough analyzing electronic characteristic of the most stable structure ,it is found that the ionization potential and energy gap are maximal values ,the H-B bridge bond key is longer than terminal linkage ,the infrared intensity of the strongest peak is maximal value of B2 H6 in B2 Hn (n=1-6) which explains that B2 H6 is the most stable boron hydride ,and the hydrogen atom differential adsorption energy is the largest and the hydrogen storage performance is the best .