• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>The journal of physical chemistry, A. Molecules, spectroscopy, kinetics, environment, & general theory >Semiempirical UNO-CAS and UNO-CI: Method and applications in nanoelectronics
【24h】

Semiempirical UNO-CAS and UNO-CI: Method and applications in nanoelectronics

机译：半经验UNO-CAS和UNO-CI：方法和在纳米电子学中的应用

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

Unrestricted Natural Orbital-Complete Active Space Configuration Interaction, abbreviated as UNO-CAS, has been implemented for NDDO-based semiempirical molecular-orbital (MO) theory. A computationally more economic technique, UNO-CIS, in which we use a configuration interaction (CI) calculation with only single excitations (CIS) to calculate excited states, has also been implemented and tested. The class of techniques in which unrestricted natural orbitals (UNOs) are used as the reference for CI calculations is denoted UNO-CI. Semiempirical UNO-CI gives good results for the optical band gaps of organic semiconductors such as polyynes and polyacenes, which are promising materials for nanoelectronics. The results of these semiempirical UNO-CI techniques are generally in better agreement with experiment than those obtained with the corresponding conventional semiempirical CI methods and comparable to or better than those obtained with far more computationally expensive methods such as time-dependent density-functional theory. We also show that symmetry breaking in semiempirical UHF calculations is very useful for predicting the diradical character of organic compounds in the singlet spin state.
机译：已为基于NDDO的半经验分子轨道（MO）理论实现了不受限制的自然轨道-完全活动空间配置交互作用（缩写为UNO-CAS）。在计算上更经济的技术，UNO-CIS，已被实施和测试，在该技术中，我们使用仅具有单个激发（CIS）的配置相互作用（CI）计算来计算激发态。将不受限制的自然轨道（UNO）用作CI计算参考的一类技术称为UNO-CI。半经验UNO-CI可为有机半导体（例如，聚炔和聚乙炔）的光学带隙提供良好的结果，而聚炔和聚并苯是纳米电子技术的有希望的材料。这些半经验UNO-CI技术的结果与实验相比，通常比用相应的常规半经验CI方法获得的结果更好地与实验相吻合，并且与用更昂贵的计算方法（例如随时间变化的密度泛函理论）获得的结果相媲美或更好。我们还表明，半经验UHF计算中的对称性破裂对于预测单线态自旋态有机化合物的双自由基特性非常有用。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号