物理化学学报 >> 1999, Vol. 15 >> Issue (08): 693-697.doi: 10.3866/PKU.WHXB19990806

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聚脲分子的非线性光学极化率

杨明理, 孙泽民, 鄢国森   

  1. 四川联合大学化学系，成都 610064
  • 收稿日期:1998-09-07 修回日期:1998-11-23 发布日期:1999-08-15
  • 通讯作者: 孙泽民

Nonlinear Optical Properties of Polyurea

Yang Ming-Li, Sun Ze-Min, Yan Guo-Sen   

  1. Department of Chemistry,Sichuan University,Chengdu 610064
  • Received:1998-09-07 Revised:1998-11-23 Published:1999-08-15
  • Contact: Sun Ze-Min

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摘要：

用ａｂ　ｉｎｉｔｉｏ／ＣＰＨＦ方法研究了尿素及其二聚体和三聚体分子的线性极化率，一阶超极化率和二阶超极化率．聚脲分子中含有多个交替排列的供电基和吸电基．计算发现，聚二脲和聚三脲较尿素具有更大的非线性光学极化系数，且其电荷分布具有新的特点，即聚脲分子由基态到激发态电荷并不发生分子范围内的长程传递，仅在局域内转移．

关键词: 从头算, 尿素, 聚脲, 非线性光学极化率, 偶极矩

Abstract:

The polarizabilities, first and second hyperpolarizabilities of urea, urea dimer and trimer have been studied by ab initio/couple perturbed Hartree-Fork (CPHF) method. A polyurea molecule contains two or more alternatively ordered electron-donating and electron-withdrawing groups. Compared to urea, its dimer and trimer possess much greater nonlinear optical susceptibilities. The calculations also show a particularly intramolecular short-range, rather than long-range, charge transfer.

Key words: Ab initio, Urea, Polyurea, Nonlinear optical property, Dipole moment