物理学报
物理學報
물이학보
2013年
7期
140-147
,共8页
王藩侯?%黄多辉%杨俊升
王藩侯?%黃多輝%楊俊升
왕번후?%황다휘%양준승
SnSe%外电场%能隙%激发特性
SnSe%外電場%能隙%激髮特性
SnSe%외전장%능극%격발특성
SnSe%external electric field%energy gap%excitation properties
对Sn原子使用SDB-cc-pVTZ基组, Se原子采用6-311++G??基组,利用密度泛函中的B3LYP方法研究了电场强度为?0.04—0.04 a.u.的外电场对SnSe基态分子的几何结构、电荷布居分布、HOMO能级、LUMO能级、能隙、费米能级、谐振频率和红外光谱强度的影响.继而使用含时密度泛函(TD-B3LYP)方法研究了SnSe分子在外场下的激发特性.结果表明,外电场的大小和方向对SnSe分子基态的这些性质有明显影响.在所加的电场范围内(?0.04 a.u.—0.04 a.u.),随着正向电场的增大,核间距先减小后增大,在F=0.03 a.u.时取得最小值0.2317 nm;分子电偶极矩μ近似线性地增大;EL, EH、费米能级EF和能隙Eg均减小.随着正向电场逐渐增大,分子总能量和谐振频率均先增大后减小;红外谱强度则先减小后增大,在F=0.03 a.u.时,取得最小值0.1138 km·mol?1.由基态到第1—10个单重激发态的波长均随着正向电场的增大而增大.激发能均随着正向电场的增大而减小.电场的引入可改变SnSe分子激发态出现的顺序并使得一些禁止的跃迁变得可能.
對Sn原子使用SDB-cc-pVTZ基組, Se原子採用6-311++G??基組,利用密度汎函中的B3LYP方法研究瞭電場彊度為?0.04—0.04 a.u.的外電場對SnSe基態分子的幾何結構、電荷佈居分佈、HOMO能級、LUMO能級、能隙、費米能級、諧振頻率和紅外光譜彊度的影響.繼而使用含時密度汎函(TD-B3LYP)方法研究瞭SnSe分子在外場下的激髮特性.結果錶明,外電場的大小和方嚮對SnSe分子基態的這些性質有明顯影響.在所加的電場範圍內(?0.04 a.u.—0.04 a.u.),隨著正嚮電場的增大,覈間距先減小後增大,在F=0.03 a.u.時取得最小值0.2317 nm;分子電偶極矩μ近似線性地增大;EL, EH、費米能級EF和能隙Eg均減小.隨著正嚮電場逐漸增大,分子總能量和諧振頻率均先增大後減小;紅外譜彊度則先減小後增大,在F=0.03 a.u.時,取得最小值0.1138 km·mol?1.由基態到第1—10箇單重激髮態的波長均隨著正嚮電場的增大而增大.激髮能均隨著正嚮電場的增大而減小.電場的引入可改變SnSe分子激髮態齣現的順序併使得一些禁止的躍遷變得可能.
대Sn원자사용SDB-cc-pVTZ기조, Se원자채용6-311++G??기조,이용밀도범함중적B3LYP방법연구료전장강도위?0.04—0.04 a.u.적외전장대SnSe기태분자적궤하결구、전하포거분포、HOMO능급、LUMO능급、능극、비미능급、해진빈솔화홍외광보강도적영향.계이사용함시밀도범함(TD-B3LYP)방법연구료SnSe분자재외장하적격발특성.결과표명,외전장적대소화방향대SnSe분자기태적저사성질유명현영향.재소가적전장범위내(?0.04 a.u.—0.04 a.u.),수착정향전장적증대,핵간거선감소후증대,재F=0.03 a.u.시취득최소치0.2317 nm;분자전우겁구μ근사선성지증대;EL, EH、비미능급EF화능극Eg균감소.수착정향전장축점증대,분자총능량화해진빈솔균선증대후감소;홍외보강도칙선감소후증대,재F=0.03 a.u.시,취득최소치0.1138 km·mol?1.유기태도제1—10개단중격발태적파장균수착정향전장적증대이증대.격발능균수착정향전장적증대이감소.전장적인입가개변SnSe분자격발태출현적순서병사득일사금지적약천변득가능.
Effects of electric field ranging from ?0.04 to 0.04 a.u., on the equilibrium structure, mulliken atomic charges, the highest occupied molecular orbital(HOMO) energy level, the lowest unoccupied molecular orbital(LUMO) energy level, energy gap, fermi energy, harmonic frequency and infrared intensities of SnSe ground state molecule are investigated by employing density functional (B3LYP) method with SDB-cc-pVTZ for Sn atom and 6-311++G**basis sets for Se atom. The magnitude and direction of the external electric field have significant effects on these characteristics of SnSe molecule. The results show that the bond length is proved to be first decreasing, and then increasing with the increase of the external field, and the minimum value is 0.2317 nm when the field strength is equal to 0.03 a.u.; electric dipole moment is found to increase linearly with the increase of external field, but the HOMO energy EH, LUMO energy EL, energy gap Egand fermi energy EF are proved to decrease with the increase of external field. The total energy and harmonic frequency are found to first increase, and then decrease, but the infrared intensities are proved to first decrease, and then increase. The wavelengths from ground state to the first ten excited states are found to increase, but the excited energies are decreasing with the increase of the external field. Meanwhile, the sequence of excited states for SnSe molecule can be changed, and some prohibited transition can be allowed under an external field.
