CAJ | 학술논문

采用密度泛函理论( DFT)方法，计算并分析了四氟取代十二顶点碳硼烷及其衍生物的结构和非线性光学( NLO)性质。结果表明，改变四氟碳硼烷取代基的共轭性或给吸电子能力，会使分子中碳硼笼原子间距离发生改变。碳硼烷取代基的给吸电子能力越强，其偶极矩越大。分子极化率随取代基共轭性和体积的增加而增大。引入强吸电子基或增加四氟碳硼烷取代基的共轭性，可使其二阶NLO响应明显增强。通过分析分子的电子光谱和对应的分子轨道组成可知，第一超极化率最大的分子4a＇发生碳硼笼到并苯取代基的电荷转移。
채용밀도범함이론( DFT)방법，계산병분석료사불취대십이정점탄붕완급기연생물적결구화비선성광학( NLO)성질。결과표명，개변사불탄붕완취대기적공액성혹급흡전자능력，회사분자중탄붕롱원자간거리발생개변。탄붕완취대기적급흡전자능력월강，기우겁구월대。분자겁화솔수취대기공액성화체적적증가이증대。인입강흡전자기혹증가사불탄붕완취대기적공액성，가사기이계NLO향응명현증강。통과분석분자적전자광보화대응적분자궤도조성가지，제일초겁화솔최대적분자4a＇발생탄붕롱도병분취대기적전하전이。
The structures and second-order nonlinear optical( NLO) properties of tetrafluoro carborane and its derivatives were investigated with density functional theory method. The results indicate that elongating the conjugation or enhancing the strength of donor( D) and acceptor( A) groups affect the distances of the carbo-rane cage. Generally speaking, the dipole moment of molecule is determined by the D/A strengths, that is, the stronger D/A groups the larger dipole moment. Meanwhile, the polarizability of each molecule increases with the increasing of the conjugation and volume of substituents. Introducing the substituents with strong elec-tron-withdrawing abilities or promoting the conjugation of substituents can effectively improve the second-order NLO coefficients. Furthermore, from the analysis of electronic absorption spectrum and the corresponding mo-lecular orbit compositions, charge transfer pattern that comes from the carborane cage to the acene substituent illustrates the first hyperpolarizability value of molecule 4a'is the largest.