Related Experiment Video
Updated: Jul 12, 2025
08:04
Excitonic Hamiltonians for Calculating Optical Absorption Spectra and Optoelectronic Properties of Molecular Aggregates and Solids
Published on: May 27, 2020
8.5K
Multipole Expansion of Atomic Electron Density Fluctuation Interactions in the Density-Functional Tight-Binding
Van-Quan Vuong1,2, Bálint Aradi3, Anders M N Niklasson4
1Department of Chemistry, Boston University, Boston, Massachusetts 02215, United States.
Journal of Chemical Theory and Computation
|October 27, 2023
Summary
The multipole-extended density-functional tight-binding (DFTB) method improves accuracy for noncovalent interactions and proton transfers. New mDFTB2 and mDFTB3 models show enhanced performance over standard DFTB methods.
Area of Science:
- Computational Chemistry
- Quantum Chemistry
- Materials Science
Background:
- The standard density-functional tight-binding (DFTB) method has limitations in accurately describing noncovalent interactions due to its reliance on monopole-based charge densities.
- Accurate modeling of noncovalent interactions is crucial for understanding molecular behavior in various chemical and biological systems.
Purpose of the Study:
- To develop and evaluate advanced DFTB methods incorporating multipole expansions for improved accuracy.
- To assess the performance of the new multipole-extended DFTB methods (mDFTB2 and mDFTB3) in describing noncovalent interactions, proton transfer barriers, and dipole moments.
Main Methods:
- Development of a multipole-extended second-order DFTB (mDFTB2) method, including atomic dipole and quadrupole interactions.
- Formulation of a multipole-extended third-order DFTB (mDFTB3) method by combining multipole expansion with monopole-based third-order contributions.
- Benchmarking the accuracy of mDFTB2 and mDFTB3 against standard DFTB2 and DFTB3 for various molecular properties.
Main Results:
- Both mDFTB2 and mDFTB3 demonstrate superior accuracy compared to their monopole-based DFTB counterparts.
- The enhanced methods show significant improvements even with existing electronic parameters.
- mDFTB3 exhibits better performance than mDFTB2 for negatively charged systems and proton transfer processes.
Conclusions:
- Incorporating multipole expansions (dipole and quadrupole) significantly enhances the accuracy of the DFTB method for noncovalent interactions.
- The developed mDFTB2 and mDFTB3 methods offer more reliable descriptions of molecular interactions and proton transfer.
- These advancements provide more accurate computational tools for studying complex chemical systems.
More Related Videos
12:11Computation of Atmospheric Concentrations of Molecular Clusters from ab initio Thermochemistry
Published on: April 8, 2020
8.2K
08:54Vibrational Spectra of a N719-Chromophore/Titania Interface from Empirical-Potential Molecular-Dynamics Simulation, Solvated by a Room Temperature Ionic Liquid
Published on: January 25, 2020
5.7K
Related Concept Videos
02:45The Quantum-Mechanical Model of an Atom
42.4K
Shortly after de Broglie published his ideas that the electron in a hydrogen atom could be better thought of as being a circular standing wave instead of a particle moving in quantized circular orbits, Erwin Schrödinger extended de Broglie’s work by deriving what is now known as the Schrödinger equation. When Schrödinger applied his equation to hydrogen-like atoms, he was able to reproduce Bohr’s expression for the energy and, thus, the Rydberg formula governing hydrogen spectra.
42.4K
03:21The Energies of Atomic Orbitals
24.0K
In an atom, the negatively charged electrons are attracted to the positively charged nucleus. In a multielectron atom, electron-electron repulsions are also observed. The attractive and repulsive forces are dependent on the distance between the particles, as well as the sign and magnitude of the charges on the individual particles. When the charges on the particles are opposite, they attract each other. If both particles have the same charge, they repel each other.
24.0K
02:46Electron Configurations
16.7K
Electron configurations and orbital diagrams can be determined by applying the Aufbau principle (each added electron occupies the subshell of lowest energy available), Pauli exclusion principle (no two electrons can have the same set of four quantum numbers), and Hund’s rule of maximum multiplicity (whenever possible, electrons retain unpaired spins in degenerate orbitals).
The relative energies of the subshells determine the order in which atomic orbitals are filled (1s, 2s, 2p, 3s, 3p,...
The relative energies of the subshells determine the order in which atomic orbitals are filled (1s, 2s, 2p, 3s, 3p,...
16.7K
02:35Molecular Orbital Theory I
32.2K
Overview of Molecular Orbital Theory
32.2K
02:44Atomic Orbitals
33.7K
An atomic orbital represents the three-dimensional regions in an atom where an electron has the highest probability to reside. The radial distribution function indicates the total probability of finding an electron within the thin shell at a distance r from the nucleus. The atomic orbitals have distinct shapes which are determined by l, the angular momentum quantum number. The orbitals are often drawn with a boundary surface, enclosing densest regions of the cloud.
33.7K
02:40MO Theory and Covalent Bonding
10.6K
The molecular orbital theory describes the distribution of electrons in molecules in a manner similar to the distribution of electrons in atomic orbitals. The region of space in which a valence electron in a molecule is likely to be found is called a molecular orbital. Mathematically, the linear combination of atomic orbitals (LCAO) generates molecular orbitals. Combinations of in-phase atomic orbital wave functions result in regions with a high probability of electron density, while...
10.6K