Partition density functional theory

Partition density functional theory (PDFT) is a method for dividing a molecular electronic structure calculation into fragment calculations. The molecular density and energy corresponding to Kohn Sham density-functional theory (KS-DFT) may be exactly recovered from these fragments. Each fragment acts as an isolated system except for the influence of a global one-body \u27partition\u27 potential which deforms the fragment densities. In this work, the developments of PDFT are put into the context of other fragment-based density functional methods. We developed three numerical implementations of PDFT: One within the NWChem computational chemistry package using basis sets, and the other two developed from scratch using real-space grids. It is shown that all three of these programs can exactly reproduce a KS-DFT calculation via fragment calculations. The first of our in-house codes handles non-interacting electrons in arbitrary one-dimensional potentials with any number of fragments. This code is used to explore how the exact partition potential changes for different partitionings of the same system and also to study features which determine which systems yield non-integer PDFT occupations and which systems are locked into integer PDFT occupations. The second in-house code, CADMium, performs real-space calculations of diatomic molecules. Features of the exact partition potential are studied for a variety of cases and an analytical formula determining singularities in the partition potential is derived. We introduce an approximation for the non-additive kinetic energy and show how this quantity can be computed exactly. Finally a PDFT functional is developed to address the issues of static correlation and delocalization errors in approximations within DFT. The functional is applied to the dissociation of H2+ and H2

State Collaboration In United States Ratification Of Human Rights Treaties

The process in the United States of negotiating and ratifying human rights treaties seldom engages the states, either individually or collectively

The Final Act of the Helsinki Conference: An Artists\u27 Liberation Movement or a Voyage to Laputa

The Final Act of the Conference on Security and Co-Operation in Europe, often referred to as the Helsinki Accords, has important implications for art and artists. The Final Act applies to three broad categories of art law issues: cultural cooperation and exchange of cultural material; the rights of individual artists; and other international cooperation. This study will examine each of these categories in the context of a current or recent problem, consider pertinent provisions of the Final Act, and conclude with a brief recommendation and forecast