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

SBIR第一阶段项目将结合从头算广义价键（GVB）或限制构型相互作用（RCI）技术和密度泛函理论（DFT）方法，研究电子结构问题的多构型密度泛函方法。GVB DFT和GVB RCI DFT软件将使用该公司PS GVB软件的伪光谱技术，允许快速计算而不损失准确性。在第一阶段，该公司将编写必要的软件，以在PS GVB的伪光谱框架中实现所提出的GVB DFT和GVB RCI DFT方法，检查来自各种功能和混合参数的结果，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。我们将研究Becke的二分之一法和三参数法的扩展，即利用GVB和GVB RCI波函数的密度对相关能进行密度泛函评价，并对三参数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基和大基集进行，包括优化的分子结构、键解离能、电离势、质子亲和、溶剂化能、多极矩、极化和超极化。这些结果将与实验或使用较不快速或较不精确的从头算和DFT方法获得的定时和精度进行比较。电子结构代码的广泛市场已经存在，研究人员对化学、生物、制药和材料应用进行从头算和DFT研究。PS GVB的相关方法扩展到GVB DFT、GVB RCI DFT和GVB RCI MP2 DFT技术，具有与其他伪光谱方法相同的高效标度，将允许快速计算化学精确的解离能、反应势垒、构象能差、力场和其他多种分子性质。因此，这项工作将大大提高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.