Spin-state splittings, highest-occupied-molecular-orbital and lowest-unoccupied-molecular-orbital energies, and chemical hardness.
Abstract
It is known that the exact density functional must give ground-state energies that
are piecewise linear as a function of electron number. In this work we prove that
this is also true for the lowest-energy excited states of different spin or spatial
symmetry. This has three important consequences for chemical applications: the ground
state of a molecule must correspond to the state with the maximum highest-occupied-molecular-orbital
energy, minimum lowest-unoccupied-molecular-orbital energy, and maximum chemical hardness.
The beryllium, carbon, and vanadium atoms, as well as the CH(2) and C(3)H(3) molecules
are considered as illustrative examples. Our result also directly and rigorously connects
the ionization potential and electron affinity to the stability of spin states.
Type
Journal articlePermalink
https://hdl.handle.net/10161/3345Published Version (Please cite this version)
10.1063/1.3497190Publication Info
Johnson, Erin R; Yang, Weitao; & Davidson, Ernest R (2010). Spin-state splittings, highest-occupied-molecular-orbital and lowest-unoccupied-molecular-orbital
energies, and chemical hardness. J Chem Phys, 133(16). pp. 164107. 10.1063/1.3497190. Retrieved from https://hdl.handle.net/10161/3345.This is constructed from limited available data and may be imprecise. To cite this
article, please review & use the official citation provided by the journal.
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Show full item recordScholars@Duke
Weitao Yang
Philip Handler Distinguished Professor of Chemistry
Prof. Yang, the Philip Handler Professor of Chemistry, is developing methods for quantum
mechanical calculations of large systems and carrying out quantum mechanical simulations
of biological systems and nanostructures. His group has developed the linear scaling
methods for electronic structure calculations and more recently the QM/MM methods
for simulations of chemical
reactions in enzymes.

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