硼氢化物(BHn)(n=1～5)稳定性与红外光谱

摘要

采用密度泛函(DFT)中的B3P86方法,结合Dunning的相关一致基组cc-PVTZ,优化计算硼氢化物(BHn)(n=1～5)可能的几何构型,得出最稳定构型的几何参数、电子结构和红外光谱等性质参数,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(Bdiff)等.结果表明硼氢化物基态稳定结构的电子态分别为:n为奇数为单重态1∑和1 A,n为偶数为双重态2A;由于B原子属于缺电子原子,能与等电子原子H化合,通过氢端或桥键形成氢化物,本文优化计算发现,硼氢化物最稳定的构型都存在氢端或桥键,且n为奇数的氢化物的氢端或桥键作用比相邻偶数的氢化物强.最后计算了硼氢化物最稳定结构的红外光谱、平均结合能、电离势、能隙和费米能级等动力学电子特性,分析得出(BHn)(n=1～5)氢化物中BH3的电离势和能隙最大,说明该氢化物最稳定,氢原子差分吸附能也最大.%The possible geometrical structure of boron hydride (BH,)(n=l~5) have been optimized computation, based on density functional theory B3P86 method and at the Dunning related consistent base group cc-PVTZ level. The configuration geometric parameter, electronic structure, vibrational frequency and spectrum of the most stable structure was obtained, and given total energy (Eτ), binding energy (EBT) > average binding energy (Eω) , ionization potential (E1P) , energy crack (Eg) , Fermi level (EF) and so on. . The result indicated that the ground state of boron hydride are 1 heavy condition when n is odd number the electronic state and they are 2 heavy condition when n is even number, respectively. In all boron hydride, there being hydrogen terminal or bridge linkage. The ultimate analysis of the infrared spectrum, the average binding energy, the ionization potential, the energy gap and Fermi level and so on characteristic. It is shown that BH3 is the most stable, molecule in (BH,)(n=1~5) for its energy gap and ionization potential are maximal values, the H -B bridge bond key long is longer than the terminal linkage, the infrared intensity of strongest peak is maximal value.