U.S.-Brazil Cooperative Science Program: Nonlinear Optical Properties of Conjugated Polymers

9217464柯特曼美国-巴西合作科学奖将支持加州大学圣巴巴拉分校的伯纳德·柯特曼和巴西伯南布哥联邦大学的塞尔索·德梅洛的合作。该项目旨在研究共轭聚合物的非线性光学性质。研究人员将制定理论方法，对这些性质进行准确、全面的描述，这些性质包括振动与振荡入射场诱导的电子极化耦合造成的失真、电子关联和非共振频率色散。这三种效应的量子化学计算都将使用有限低聚物方法对原型式的pi共轭聚合物--反式聚乙炔进行。还将研究绕过此程序所需外推的传递矩阵法。美国和巴西双方都将了解高强度光辐射和共轭聚合物之间的相互作用，这可能会改进实际用途的聚合物材料的设计。双方的学生和博士后都将受益于非传统聚合物方法的培训。***

9217464 Kirtman This U.S.-Brazil Cooperative Science award will support the collaboration of Bernard Kirtman of the University of California at Santa Barbara and Celso de Melo of the Federal University of Pernambuco, Brazil. The project aims to investigate the nonlinear optical properties of conjugated polymers. The researchers will formulate theoretical methods that permit an accurate, comprehensive description of these properties, which include distortion due to coupling of vibrations with electronic polarization induced by the oscillatory incident field(s); electron correlation; and non-resonant frequency dispersion. Ab initio quantum chemistry calculations of all three effects will be done for the prototype pi-conjugated polymer, trans- polyacetylene using the finite oligomer approach. A transfer matrix method for circumventing the extrapolations required with this procedure will also be investigated. Both the U.S. and Brazilian sides will gain an understanding of the interaction between high intensity optical radiation and conjugated polymers, which could potentially improve the design of polymeric materials for practical purposes. Students and postdocs on both sides will benefit from training in non-conventional polymer methodologies. ***