1
|
Mrovec M, Gill PMW. How delocalized are the polyacenes? J Comput Chem 2024; 45:701-709. [PMID: 38100265 DOI: 10.1002/jcc.27258] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2023] [Revised: 10/31/2023] [Accepted: 11/01/2023] [Indexed: 12/17/2023]
Abstract
In an attempt to quantify electron delocalization in polyacenes with up to 50 carbon atoms, we have performed self-consistent field calculations in which the π electrons are constrained to occupy highly localized molecular orbitals (HILOs) centered on a maximum of two, six or ten adjacent carbon atoms. We have also performed similar calculations on simple polyacene analogs consisting only of hydrogen atoms and exhibiting electron delocalization in the σ framework. We find that the energetic cost of localizing the π electrons in the polyacenes is roughly 60, 5 or 0.1 kJ/mol per ring atom for the two-, six- and ten-atom HILOs, respectively, and the use of these localized models overestimates the predicted hydrogenation energies of the acenes by roughly 50%, 4% and 0.1%, respectively. We conclude that the chemistry of polyacenes can be modeled well using highly localized descriptions of the π electrons.
Collapse
Affiliation(s)
- Martin Mrovec
- School of Chemistry, University of Sydney, Camperdown, New South Wales, Australia
| | - Peter M W Gill
- School of Chemistry, University of Sydney, Camperdown, New South Wales, Australia
| |
Collapse
|
2
|
White SR, Lindsey MJ. Nested gausslet basis sets. J Chem Phys 2023; 159:234112. [PMID: 38108488 DOI: 10.1063/5.0180092] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2023] [Accepted: 11/26/2023] [Indexed: 12/19/2023] Open
Abstract
We introduce nested gausslet bases, an improvement on previous gausslet bases that can treat systems containing atoms with much larger atomic numbers. We also introduce pure Gaussian distorted gausslet bases, which allow the Hamiltonian integrals to be performed analytically, as well as hybrid bases in which the gausslets are combined with standard Gaussian-type bases. All these bases feature the diagonal approximation for the electron-electron interactions so that the Hamiltonian is completely defined by two Nb × Nb matrices, where Nb ≈ 104 is small enough to permit fast calculations at the Hartree-Fock level. In constructing these bases, we have gained new mathematical insight into the construction of one-dimensional diagonal bases. In particular, we have proved an important theorem relating four key basis set properties: completeness, orthogonality, zero-moment conditions, and diagonalization of the coordinate operator matrix. We test our basis sets on small systems with a focus on high accuracy, obtaining, for example, an accuracy of 2 × 10-5 Ha for the total Hartree-Fock energy of the neon atom in the complete basis set limit.
Collapse
Affiliation(s)
- Steven R White
- Department of Physics and Astronomy, University of California, Irvine, California 92697-4575, USA
| | - Michael J Lindsey
- Department of Mathematics, University of California, Berkeley, California 94720, USA
| |
Collapse
|
3
|
Li Y, Li C. Exact Analytical Form of Diatomic Molecular Orbitals. ACS OMEGA 2022; 7:22594-22600. [PMID: 35811915 PMCID: PMC9260940 DOI: 10.1021/acsomega.2c01905] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/29/2022] [Accepted: 05/24/2022] [Indexed: 06/15/2023]
Abstract
We provide the exact analytical form of diatomic molecular orbitals, as given by the solutions of a single-electron diatomic molecule with arbitrary nuclear charges, using our recently developed method for solving Schrödinger equations. We claim that the best representation of the wave function is a factorized form including a power prefactor, an exponentially decaying term, a modulator function on the exponential, and additional factors accounting for nodal surfaces and the magnetic quantum number. Applying our method, we have identified unexpected extreme points along the potential energy curves, hence revealing the limitations of the well-known concepts of bonding and antibonding.
Collapse
Affiliation(s)
- Yunzhi Li
- Beijing
National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China
| | - Chen Li
- Beijing
National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China
| |
Collapse
|
4
|
A new method for theoretical calculation of atomic hyperfine structure. Chem Phys 2022. [DOI: 10.1016/j.chemphys.2022.111485] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
|
5
|
Conflict and agreement in the exact solutions of Schrodinger equation in a two and restricted three-body systems. Chem Phys Lett 2022. [DOI: 10.1016/j.cplett.2022.139514] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
|
6
|
Fernández FM, Garcia J. Highly Accurate Potential Energy Curves for the Hydrogen Molecular Ion. ChemistrySelect 2021. [DOI: 10.1002/slct.202102509] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Francisco M. Fernández
- División Química Teórica Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas Diagonal 113 y 64 S/N 1900 La Plata Argentina
| | - Javier Garcia
- División Química Teórica Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas (INIFTA) Diagonal 113 y 64 S/N 1900 La Plata Argentina
| |
Collapse
|
7
|
Mitnik DM, López FA, Ancarani LU. Generalized Sturmian Functions in prolate spheroidal coordinates. Mol Phys 2021. [DOI: 10.1080/00268976.2021.1881179] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Affiliation(s)
- D. M. Mitnik
- Instituto de Astronomía y Física del Espacio (IAFE), CONICET-UBA, Buenos Aires, Argentina
| | - F. A. López
- Instituto de Astronomía y Física del Espacio (IAFE), CONICET-UBA, Buenos Aires, Argentina
| | | |
Collapse
|
8
|
Excited states for hydrogen ion molecule confined by a prolate spheroidal boxes: variational approach. Theor Chem Acc 2020. [DOI: 10.1007/s00214-020-02645-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
|
9
|
Price TJ, Greene CH. Semiclassical Treatment of High-Lying Electronic States of H 2. J Phys Chem A 2018; 122:8565-8575. [PMID: 30299945 DOI: 10.1021/acs.jpca.8b07878] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We report quantum-mechanical and semiclassical WKB calculations for energies and wave functions of high-lying 2Σ states of H2+ in atomic units. The high-lying states we present lie in an unexplored regime, corresponding asymptotically to H ( n ≤ 146) plus a proton, with R ≤ 120 000 a0. We compare quantum-mechanical energies, spectroscopic constants, dipole matrix elements, and phases with semiclassical results and demonstrate a high level of agreement. Our quantum-mechanical phases were determined by using Milne's phase-amplitude procedure. We compare our semiclassical energies for low-lying states with those of other researchers.
Collapse
Affiliation(s)
- T J Price
- Department of Physics and Astronomy , Purdue University , West Lafayette , Indiana 47907 , United States
| | - Chris H Greene
- Department of Physics and Astronomy , Purdue University , West Lafayette , Indiana 47907 , United States.,Purdue Quantum Center , Purdue University , West Lafayette , Indiana 47907 , United States
| |
Collapse
|
10
|
Fermi-Löwdin orbital self-interaction corrected density functional theory: Ionization potentials and enthalpies of formation. J Comput Chem 2018; 39:2463-2471. [DOI: 10.1002/jcc.25586] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2018] [Revised: 08/15/2018] [Accepted: 08/16/2018] [Indexed: 11/07/2022]
|
11
|
Jones RO. Bonding in phase change materials: concepts and misconceptions. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2018; 30:153001. [PMID: 29480162 DOI: 10.1088/1361-648x/aab22e] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Bonding concepts originating in chemistry are surveyed from a condensed matter perspective, beginning around 1850 with 'valence' and the word 'bond' itself. The analysis of chemical data in the 19th century resulted in astonishing progress in understanding the connectivity and stereochemistry of molecules, almost without input from physicists until the development of quantum mechanics in 1925 and afterwards. The valence bond method popularized by Pauling and the molecular orbital methods of Hund, Mulliken, Bloch, and Hückel play major roles in the subsequent development, as does the central part played by the kinetic energy in covalent bonding (Ruedenberg and others). 'Metallic' (free electron) and related approaches, including pseudopotential and density functional theories, have been remarkably successful in understanding structures and bonding in molecules and solids. We discuss these concepts in the context of phase change materials, which involve the rapid and reversible transition between amorphous and crystalline states, and note the confusion that some have caused, in particular 'resonance' and 'resonant bonding'.
Collapse
Affiliation(s)
- R O Jones
- Peter-Grünberg-Institut PGI-1 and JARA/HPC, Forschungszentrum Jülich, D-52425 Jülich, Germany
| |
Collapse
|
12
|
Scott T, Zhang X, Mann R, Fee G. Canonical reduction for dilatonic gravity in3+1dimensions. Int J Clin Exp Med 2016. [DOI: 10.1103/physrevd.93.084017] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
|
13
|
Abstract
Orbital basis functions in a one-dimensional triatomic molecule ABC.
Collapse
Affiliation(s)
- Pierre-François Loos
- Research School of Chemistry
- Australian National University
- Canberra ACT 0200
- Australia
| | - Caleb J. Ball
- Research School of Chemistry
- Australian National University
- Canberra ACT 0200
- Australia
| | - Peter M. W. Gill
- Research School of Chemistry
- Australian National University
- Canberra ACT 0200
- Australia
| |
Collapse
|
14
|
|
15
|
Schmidt MW, Ivanic J, Ruedenberg K. Covalent bonds are created by the drive of electron waves to lower their kinetic energy through expansion. J Chem Phys 2014; 140:204104. [PMID: 24880263 PMCID: PMC4032414 DOI: 10.1063/1.4875735] [Citation(s) in RCA: 64] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2014] [Accepted: 04/29/2014] [Indexed: 12/16/2022] Open
Abstract
An analysis based on the variation principle shows that in the molecules H2 (+), H2, B2, C2, N2, O2, F2, covalent bonding is driven by the attenuation of the kinetic energy that results from the delocalization of the electronic wave function. For molecular geometries around the equilibrium distance, two features of the wave function contribute to this delocalization: (i) Superposition of atomic orbitals extends the electronic wave function from one atom to two or more atoms; (ii) intra-atomic contraction of the atomic orbitals further increases the inter-atomic delocalization. The inter-atomic kinetic energy lowering that (perhaps counter-intuitively) is a consequence of the intra-atomic contractions drives these contractions (which per se would increase the energy). Since the contractions necessarily encompass both, the intra-atomic kinetic and potential energy changes (which add to a positive total), the fact that the intra-atomic potential energy change renders the total potential binding energy negative does not alter the fact that it is the kinetic delocalization energy that drives the bond formation.
Collapse
Affiliation(s)
- Michael W Schmidt
- Department of Chemistry and Ames Laboratory USDOE, Iowa State University, Ames, Iowa 50011, USA
| | - Joseph Ivanic
- Advanced Biomedical Computing Center, Information Systems Program, Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research, Frederick, Maryland 21702, USA
| | - Klaus Ruedenberg
- Department of Chemistry and Ames Laboratory USDOE, Iowa State University, Ames, Iowa 50011, USA
| |
Collapse
|
16
|
Affiliation(s)
- Zbigniew Romanowski
- a Interdisciplinary Centre for Mathematical and Computational Modelling , Pawinskiego 5a, 02-106 Warsaw , Poland
| |
Collapse
|
17
|
Ruedenberg K, Schmidt MW. Physical understanding through variational reasoning: electron sharing and covalent bonding. J Phys Chem A 2010; 113:1954-68. [PMID: 19228050 DOI: 10.1021/jp807973x] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Energy changes of stationary states resulting from geometric parameter changes in the Hamiltonian can be understood by variational reasoning in terms of the physical attributes of the kinetic and the potential energy functionals. In atoms as well as molecules, the energy minimization determines the ground state as the optimal compromise between the potential pull of the nuclear attractions and the localization-resisting kinetic pressure of the electron cloud. This variational competition is analyzed for the exact ab initio ground-state wave function of the hydrogen molecule ion to elucidate the formation of the bond. Its electronic wave function is shown to differ from the ground-state wave function of the hydrogen atom by polarization, sharing, and contraction, and the corresponding contributions to the binding energy are examined in detail. All told, the critical feature is that a molecular orbital, contracting (in the variational context) toward two nuclei simultaneously, can lower its potential energy while maintaining a certain degree of delocalization. As a consequence, its kinetic energy functional has a lower value than that of an orbital contracting toward a single nucleus equally closely. By contrast, the potential energy functional is lowered equally effectively whether the orbital contracts toward one nucleus or simultaneously toward two nuclei. Because of this weaker kinetic energy pressure, the electrostatic potential pull of the nuclei in the molecule is able to attach the orbital more tightly to each of the nuclei than the pull of the single nucleus in the atom is able to do. The role of the virial theorem is clarified. Generalizations to other molecules are discussed.
Collapse
Affiliation(s)
- Klaus Ruedenberg
- Department of Chemistry and Ames Laboratory, United States Department of Energy, Iowa State University, Ames, Iowa 50011, USA
| | | |
Collapse
|
18
|
Ruedenberg K, Schmidt MW. Why does electron sharing lead to covalent bonding? A variational analysis. J Comput Chem 2007; 28:391-410. [PMID: 17143869 DOI: 10.1002/jcc.20553] [Citation(s) in RCA: 80] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Ground state energy differences between related systems can be elucidated by a comparative variational analysis of the energy functional, in which the concepts of variational kinetic pressure and variational electrostatic potential pull are found useful. This approach is applied to the formation of the bond in the hydrogen molecule ion. A highly accurate wavefunction is shown to be the superposition of two quasiatomic orbitals, each of which consists to 94% of the respective atomic 1s orbital, the remaining 6% deformation being 73% spherical and 27% nonspherical in character. The spherical deformation can be recovered to 99.9% by scaling the 1s orbital. These results quantify the conceptual metamorphosis of the free-atom wavefunction into the molecular wavefunction by orbital sharing, orbital contraction, and orbital polarization. Starting with the 1s orbital on one atom as the initial trial function, the value of the energy functional of the molecule at the equilibrium distance is stepwise lowered along several sequences of wavefunction modifications, whose energies monotonically decrease to the ground state energy of H2+. The contributions of sharing, contraction and polarization to the overall lowering of the energy functional and their kinetic and potential components exhibit a consistent pattern that can be related to the wavefunction changes on the basis of physical reasoning, including the virial theorem. It is found that orbital sharing lowers the variational kinetic energy pressure and that this is the essential cause of covalent bonding in this molecule.
Collapse
Affiliation(s)
- Klaus Ruedenberg
- Department of Chemistry and Ames Laboratory USDOE, Iowa State University, Ames, Iowa 50011, USA.
| | | |
Collapse
|