SBIR PHASE I: Novel Electron Correlation Methods: Multiconfigurational Density Functional Theory

这个SBIR第一阶段项目将产生一种多组态密度泛函方法来解决电子结构问题，它将从头算广义价键(GVB)或限制组态相互作用(RCI)技术与密度泛函理论(DFT)方法相结合。GVB DFT和GVB RCI DFT软件将使用该公司PS GVB软件的伪谱技术，以实现快速计算而不会损失精度。在第一阶段，该公司将编写在PS GVB的伪谱框架中实施建议的GVB DFT和GVB RCI DFT方法所需的软件，检查来自各种泛函和杂化参数的结果，并使用这些方法执行一些分子性质的初步计算，以说明其可行性、速度和准确性。我们将考察Becke的半参数方法和三参数方法在关联能密度泛函计算中的推广，并对三种参数方法的各种参数进行测试。大分子的各种性质的计算将使用中等和大的基组，包括优化的分子结构、键解离能、电离势、质子亲和势、溶剂化能、多极矩、极化率和超极化率。这些结果将与实验或与使用不太快速或不太准确的从头算和密度泛函方法获得的时间和精度进行比较。电子结构代码已经存在一个广泛的市场，研究人员进行化学、生物、制药和材料应用的从头算和密度泛函研究。将PS GVB的相关方法扩展到GVB DFT、GVB RCI DFT和GVB RCI MP2 DFT技术，并使用其他伪谱方法已经存在的相同有效标度，将允许快速计算化学上准确的离解能、反应势垒、构象能差、力场和多种其他分子性质。因此，这项工作将极大地增强PS GVB的市场。

This SBIR Phase I project will result in a multiconfigurational density functional approach to electronic structure problems that combines ab initio generalized valence bond (GVB) or restricted configuration interaction (RCI) techniques with density functional theory (DFT) methods. The GVB DFT and GVB RCI DFT software will use the pseudospectral techniques of this firm's PS GVB software to allow rapid calculations without loss of accuracy. In Phase I, this firm will write the software necessary to implement the proposed GVB DFT and GVB RCI DFT methods in PS GVB's pseudospectral framework, examine results from various functionals and hybrid parameters, and use the methods to perform some preliminary calculations of molecular properties to illustrate its feasibility, speed, and accuracy. Extensions of Becke's half half and three parameter methods that employ densities from GVB and GVB RCI wave functions in the density functional evaluation of the correlation energy will be examined, and various parameters for the three parameter methods will be tested. Calculations of various properties of large molecules will be performed using medium and large basis sets, including optimized molecular structures, bond dissociation energies, ionization potentials, proton affinities, solvation energies, multipole moments, polarizabilities, and hyperpolarizabilities. These results will be compared to experiment or to timing and accuracy obtained using less rapid or less accurate ab initio and DFT methods. An extensive market already exists for electronic structure codes, with researchers performing ab initio and DFT studies for chemical, biological, pharmaceutical, and materials applications. The extension of PS GVB's correlation methods to GVB DFT, GVB RCI DFT, and GVB RCI MP2 DFT techniques with the same efficient scaling already present for other pseudospectral methods would permit rapid calculation of chemically accurate dissociation energies, reaction barriers, conformational energy differences, force fields, and multiple other molecular properties. Consequently, this work will enhance the market for PS GVB significantly.