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Approximate solution of the many-electron molecular or material Hamiltonian for energies, states, densities, and response properties.
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This is an authored directed relation from the source endpoint to the target endpoint.
A basis set turns the electronic-structure equations into a finite numerical problem, and its completeness, functional form, and treatment of diffuse or core regions affect the computed result.
The source supplies a substantive formal ingredient, dynamical sector, law, field content, or mechanism of the target theoretical framework.
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At each nuclear geometry the approximation supplies an electronic eigenproblem, with nuclear dynamics then propagated on one or more surfaces.
A theory, law, or interaction describes the behavior of the target within a stated regime. The edge detail must state important limits or qualifications.
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Ab initio methods form a broad class of electronic-structure calculations distinguished from empirical or semiempirical parametrizations.
The target is a member or subtype of the broader source class.
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Configuration interaction expands a state in determinants or configuration-state functions; truncation controls cost but usually sacrifices size extensivity.
The target is a model, idealization, restricted ansatz, approximation scheme, phenomenological fit, or historical representation used for the source system or theory. It need not have a universal small error parameter and is not thereby a controlled limit or effective theory. The edge label and detail must identify the precise status.
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Coupled-cluster methods use an exponential excitation operator and give systematically improvable, size-extensive approximations within suitable regimes.
The target is a model, idealization, restricted ansatz, approximation scheme, phenomenological fit, or historical representation used for the source system or theory. It need not have a universal small error parameter and is not thereby a controlled limit or effective theory. The edge label and detail must identify the precise status.
wp-chem-quantum-chemistryiupac-green-booknist-chemistry-webbookThis is an authored directed relation from the source endpoint to the target endpoint.
Density-functional calculations infer ground-state properties from electron density with accuracy controlled by the chosen functional and numerical model.
The target is a member or subtype of the broader source class.
wp-chem-quantum-chemistryiupac-green-booknist-chemistry-webbookThis is an authored directed relation from the source endpoint to the target endpoint.
Density-functional calculations replace the many-electron wavefunction as the basic variable with the density, while practical accuracy depends on approximate functionals.
The target is a model, idealization, restricted ansatz, approximation scheme, phenomenological fit, or historical representation used for the source system or theory. It need not have a universal small error parameter and is not thereby a controlled limit or effective theory. The edge label and detail must identify the precise status.
wp-chem-quantum-chemistryiupac-green-booknist-chemistry-webbookThis is an authored directed relation from the source endpoint to the target endpoint.
Hartree–Fock approximates the many-electron state by an optimized Slater determinant and omits correlation beyond exchange.
The target is a model, idealization, restricted ansatz, approximation scheme, phenomenological fit, or historical representation used for the source system or theory. It need not have a universal small error parameter and is not thereby a controlled limit or effective theory. The edge label and detail must identify the precise status.
wp-chem-quantum-chemistryiupac-green-booknist-chemistry-webbookThis is an authored directed relation from the source endpoint to the target endpoint.
Electronic-structure calculations help decompose periodic trends while remaining dependent on Hamiltonian, basis, correlation, and relativistic treatment.
A theory, law, or interaction describes the behavior of the target within a stated regime. The edge detail must state important limits or qualifications.
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