scholarly journals Mulliken-Dipole Population Analysis

2020 ◽  
Author(s):  
Daniel G Trabada ◽  
Diego Soler-Polo ◽  
Jesus I. Mendieta-Moreno ◽  
José Ortega
Keyword(s):  
Dipole Moment ◽  
Good Description ◽  
Dipole Moments ◽  
Population Analysis ◽  
Atomic Charge ◽  
Atomistic Simulations ◽  
Atomic Charges ◽  
Mulliken Population ◽  
Basic Hypothesis ◽  
Bond Direction

Atomic charge is one of the most important concepts in Chemistry. Mulliken population analysis is historically the most important method to calculate atomic charges and is still widely used. One basic hypothesis of this method is the half-and-half partition of the overlap populations, Q(μ, <i>v</i>), into equal charges in orbitals μ and <i>v</i>. This partition preserves the monopole moment of the overlap density but, other than that, is arbitrary. In this work we derive a new population analysis (which we designate Mulliken-Dipole population analysis) based on the conservation of both the monopole moment and the dipole moment along the bond direction. Test calculations show that the Mulliken-Dipole atomic charges are in accord to the chemical intuition; also they are very different from the Mulliken ones, being quite similar to the Hirshfeld atomic charges. Mulliken-Dipole atomic charges are conceptually appealing and very easy to calculate. In a further step, we also show how this Mulliken-Dipole population analysis can be used to derive atomic charges for atomistic simulations that reproduce the total dipole moment of the molecule, yielding at the same time a good description of the local charges and dipole moments for the molecular fragments.<br>

scholarly journals Mulliken-Dipole Population Analysis

2020 ◽  
Author(s):  
Daniel G Trabada ◽  
Diego Soler-Polo ◽  
Jesus I. Mendieta-Moreno ◽  
José Ortega
Keyword(s):  
Dipole Moment ◽  
Good Description ◽  
Dipole Moments ◽  
Population Analysis ◽  
Atomic Charge ◽  
Atomistic Simulations ◽  
Atomic Charges ◽  
Mulliken Population ◽  
Basic Hypothesis ◽  
Bond Direction

Atomic charge is one of the most important concepts in Chemistry. Mulliken population analysis is historically the most important method to calculate atomic charges and is still widely used. One basic hypothesis of this method is the half-and-half partition of the overlap populations, Q(μ, <i>v</i>), into equal charges in orbitals μ and <i>v</i>. This partition preserves the monopole moment of the overlap density but, other than that, is arbitrary. In this work we derive a new population analysis (which we designate Mulliken-Dipole population analysis) based on the conservation of both the monopole moment and the dipole moment along the bond direction. Test calculations show that the Mulliken-Dipole atomic charges are in accord to the chemical intuition; also they are very different from the Mulliken ones, being quite similar to the Hirshfeld atomic charges. Mulliken-Dipole atomic charges are conceptually appealing and very easy to calculate. In a further step, we also show how this Mulliken-Dipole population analysis can be used to derive atomic charges for atomistic simulations that reproduce the total dipole moment of the molecule, yielding at the same time a good description of the local charges and dipole moments for the molecular fragments.<br>

scholarly journals Fast Atomic Charge Calculation for Implementation into a Polarizable Force Field and Application to an Ion Channel Protein

2015 ◽  
Vol 2015 ◽  
pp. 1-14 ◽  
Author(s):  
Raiker Witter ◽  
Margit Möllhoff ◽  
Frank-Thomas Koch ◽  
Ulrich Sternberg
Keyword(s):  
Force Field ◽  
Influenza A ◽  
Transmembrane Domain ◽  
Population Analysis ◽  
3D Structure ◽  
Atomic Charge ◽  
Basis Set ◽  
Atomic Charges ◽  
Molecular Mechanics Calculations ◽  
Activated State

Polarization of atoms plays a substantial role in molecular interactions. Class I and II force fields mostly calculate with fixed atomic charges which can cause inadequate descriptions for highly charged molecules, for example, ion channels or metalloproteins. Changes in charge distributions can be included into molecular mechanics calculations by various methods. Here, we present a very fast computational quantum mechanical method, the Bond Polarization Theory (BPT). Atomic charges are obtained via a charge calculation method that depend on the 3D structure of the system in a similar way as atomic charges ofab initiocalculations. Different methods of population analysis and charge calculation methods and their dependence on the basis set were investigated. A refined parameterization yielded excellent correlation ofR=0.9967. The method was implemented in the force field COSMOS-NMR and applied to the histidine-tryptophan-complex of the transmembrane domain of the M2 protein channel of influenza A virus. Our calculations show that moderate changes of side chain torsion angleχ1and small variations ofχ2of Trp-41 are necessary to switch from the inactivated into the activated state; and a rough two-side jump model of His-37 is supported for proton gating in accordance with a flipping mechanism.

Molecular Structural and Vibrational Spectroscopic Assignments of n5-(4-Methoxyphenyl)-3-(1-methylindol-3-yl)-isoxazole using DFT Theory Calculations

2019 ◽  
Vol 4 (3) ◽  
pp. 147-151
Author(s):  
J. Jani Matilda ◽  
T.F. Abbs Fen Reji
Keyword(s):  
Molecular Orbital ◽  
Density Functional ◽  
Population Analysis ◽  
Nbo Analysis ◽  
Basis Set ◽  
Atomic Charges ◽  
Dft Methods ◽  
Mulliken Population ◽  
B3lyp Method ◽  
Experimental Values

In an effort to evaluate and design fast, accurate density functional theory (DFT) methods for 5-(4- methoxyphenyl)-3-(1-methylindol-3yl)isoxazole compound was done using Gaussion’ 09 program package using B3LYP method with the 6-31G basis set, which has been successfully applied in order to derive the optimized geometry, bonding features, harmonic vibrational wave numbers, NBO analysis and Mulliken population analysis on atomic charges in the ground state. Optimized geometries of the molecule have been described and collate with the experimental values. The experimental atomic charges demonstrates adequate concurrence with the theoretical prediction from DFT. The theoretical spectra values have been interpreted and compared with the FT-IR spectra. The calculated highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) energy gaps also confirm that charge transfer takes place within the molecule.

scholarly journals COMPARAÇÃO ENTRE MÉTODOS PARA DETERMINAÇÃO DE CARGAS ATÔMICAS EM SISTEMAS MOLECULARES: A MOLÉCULA N-{N-(PTERINA-7-IL)CARBONILGLICIL}-L-TIROSINA (NNPT)

Química Nova ◽  
2020 ◽  
Author(s):  
Fernanda Botelho ◽  
Roberta Oliveira ◽  
Joyce Almeida ◽  
Tanos França ◽  
Itamar Borges
Keyword(s):  
Dipole Moment ◽  
Atomic Charge ◽  
Basis Sets ◽  
Atomic Charges ◽  
Resonance Effects ◽  
Molecular Systems ◽  
Moment Vector ◽  
Different Types ◽  
Partial Atomic Charges ◽  
Charge Calculations

COMPARISON BETWEEN ATOMIC CHARGE METHODS FOR MOLECULAR SYSTEMS: THE N-{N-(PTERIN-7-YL) CARBONYLGLYCYL}-L-TYROSINE (NNPT) MOLECULE. Selecting a method to compute partial atomic charges is not trivial because different methods usually provide different charge values and there is no consensus on the most useful approach. In this work, Mulliken, MBS, Chelp, Chelpg, MK, Hirshfeld, NPA, DMA and AIM methods were selected to compute atomic charges and electric dipole moment vector of N-{N-(Pterin-7-yl)carbonylglycyl}-L-tyrosine molecule, a ricin inhibitor which has different types of bonds and chemical environments. While MBS and DMA methods provided the most chemically consistent charges according to atomic electronegativity and electron resonance effects criteria, Chelp, Chelpg and MK had the worst performances. Atomic charges and dipole moment calculated by the Hirshfeld method had the smallest magnitudes, a well-known behavior. Despite the differences among atomic charges predicted by all methods, the direction of the dipole moment vector was essentially the same. Further charge calculations using different basis sets and quantum methods indicated that the dependency on this aspect was the highest for Mulliken and Chelp and the lowest for MBS, Hirshfeld and DMA methods. Thus, results point to MBS and DMA as the most suitable methods for computing chemically consistent atomic charges and dipole moment vectors of similar systems for different applications; e.g., molecular dynamics.

A Computational Study on Structural and Electronic Properties of 1-(4-Chlorophenyl)-2-{[5-(4-Chlorophenyl)-1,2,3-Oxadiazol-2-Yl]Sulfanyl}Ethanone

2019 ◽  
Vol 892 ◽  
pp. 1-7
Author(s):  
Pek Lan Toh ◽  
Montha Meepripruk ◽  
Rosfayanti Rasmidi
Keyword(s):  
Density Functional ◽  
Computational Study ◽  
Molecular System ◽  
Population Analysis ◽  
Atomic Charge ◽  
Dft Method ◽  
Basis Sets ◽  
Hydrogen Atoms ◽  
Mulliken Population ◽  
Total Energies

In this paper, a first principle Density Functional Theory (DFT) method was conducted to study the geometric and electronic structures of 1-(4-chlorophenyl)-2-{[5-(4-chlorophenyl) -1,3,4-oxadiazol-2-yl] sulfanyl} ethanone, C16H10Cl2N2O2S. Using B3LYP level of theory with four basis sets of 6-31G**, 6-31++G**, 6-311G**, and 6-311++G**, the equilibrium structure of the title molecule was used to determine the total energies, Frontier molecular orbital’s energies, Mulliken atomic charges, and others. The computed findings present that four total energies obtained are close to each other, with the corresponding values of-59716.06 eV, -59709.42 eV, -59708.56 eV, and-59716.51 eV, respectively for B3LYP/6-31G**, B3LYP/6-31++G**, B3LYP/6-311G**, and B3LYP/6-311++G** methods. The calculated HOMO-LUMO energy gaps were predicted in the range of 4.001 eV - 4.089 eV. In this study, the atomic charge values of molecular system were also determined using Mulliken Population Analysis (MPA) approach. For DFT/B3LYP/6-311G** level of calculation, the computed results show that the atom of C8 accommodates the highest negative charge in the title molecular system. All the oxygen, nitrogen, and chloride atoms are having negative charges, whereas all the hydrogen atoms are having positive charges. In addition, the dipole moment value was also determined to be 1.4758 Debye by employing DFT/B3LYP/6-311G** level of theory.

Theoritical ab initio study of Internal Rotation Barriers, Structures Stabilities and Population of Formamide

2002 ◽  
Vol 2002 (8) ◽  
pp. 403-406
Author(s):  
Majid Monajjemi ◽  
Halleh H. Haeri ◽  
Malihe T. Azad
Keyword(s):  
Population Analysis ◽  
Atomic Charges ◽  
Mulliken Population Analysis ◽  
Ab Initio Study ◽  
Bond Energies ◽  
Mulliken Population ◽  
Natural Population Analysis ◽  
Nbo Method ◽  
Internal Rotational Barriers ◽  
Good Agreement

The internal rotational barriers for formamide are calculated in gas and solution phases (acetonitrile) at the HF/6-31G* (16.64 and 16.18 kcal/mol, respectively) and MP2/6-31G* (16.86 and 16.71 kcal/ mol, respectively) level of theory. Calculated parameters are compared with experimental data and there is a good agreement between them. Orbital populations are obtained by MPA (mulliken population analysis) and NPA (natural population analysis) methods and bond energies are calculated by the NBO method (natural bond orbitals). The distribution of atomic charges are also given. These calculation indicate that the internal rotational barrier is produced because of change in the distribution of orbital populations of 2p y, 2p z, d yz, d y2 and dz2 orbitals of the nitrogen atom.

A simple model for calculating atomic charges in molecules

2018 ◽  
Vol 20 (36) ◽  
pp. 23328-23337 ◽  
Author(s):  
Alexander A. Voityuk ◽  
Anton J. Stasyuk ◽  
Sergei F. Vyboishchikov
Keyword(s):  
Simple Model ◽  
Dipole Moments ◽  
Atomic Charge ◽  
Atomic Charges ◽  
Analysis Scheme ◽  
Charge Analysis ◽  
Two Parameters

An atomic-charge analysis scheme with two parameters per element is proposed. The scheme reproduces well the experimental dipole moments.

Net atomic charges and molecular dipole moments from spherical-atom X-ray refinements, and the relation between atomic charge and shape

1979 ◽  
Vol 35 (1) ◽  
pp. 63-72 ◽  
Author(s):  
P. Coppens ◽  
T. N. Guru Row ◽  
P. Leung ◽  
E. D. Stevens ◽  
P. J. Becker ◽  
...  
Keyword(s):  
Dipole Moments ◽  
Atomic Charge ◽  
Atomic Charges ◽  
Molecular Dipole ◽  
X Ray

Energies and Electric Dipole Moments of the Bound Vibrational States of HN2+ and DN2+

2008 ◽  
Vol 73 (6-7) ◽  
pp. 873-897 ◽  
Author(s):  
Vladimír Špirko ◽  
Ota Bludský ◽  
Wolfgang P. Kraemer
Keyword(s):  
Dipole Moment ◽  
Nearest Neighbor ◽  
Energy Surface ◽  
Dipole Moments ◽  
Three Dimensional ◽  
Vibrational States ◽  
Spacing Distribution ◽  
Triatomic Molecules ◽  
Vibrational Levels ◽  
Different Levels

The adiabatic three-dimensional potential energy surface and the corresponding dipole moment surface describing the ground electronic state of HN2+ (Χ1Σ+) are calculated at different levels of ab initio theory. The calculations cover the entire bound part of the potential up to its lowest dissociation channel including the isomerization barrier. Energies of all bound vibrational and low-lying ro-vibrational levels are determined in a fully variational procedure using the Suttcliffe-Tennyson Hamiltonian for triatomic molecules. They are in close agreement with the available experimental numbers. From the dipole moment function effective dipoles and transition moments are obtained for all the calculated vibrational and ro-vibrational states. Statistical tools such as the density of states or the nearest-neighbor level spacing distribution (NNSD) are applied to describe and analyse general patterns and characteristics of the energy and dipole results calculated for the massively large number of states of the strongly bound HN2+ ion and its deuterated isotopomer.

scholarly journals Ni Oxidation State and Ligand Saturation Impact on the Capability of Octaazamacrocyclic Complexes to Bind and Reduce CO2

Molecules ◽  
2021 ◽  
Vol 26 (14) ◽  
pp. 4139
Author(s):  
Barbora Vénosová ◽  
Ingrid Jelemenská ◽  
Jozef Kožíšek ◽  
Peter Rapta ◽  
Michal Zalibera ◽  
...  
Keyword(s):  
Quantum Theory ◽  
Oxidation State ◽  
Central Atom ◽  
Population Analysis ◽  
Mulliken Population Analysis ◽  
Mulliken Population ◽  
Theoretical Methods ◽  
Ni Oxidation ◽  
Shed Light

Two 15-membered octaazamacrocyclic nickel(II) complexes are investigated by theoretical methods to shed light on their affinity forwards binding and reducing CO2. In the first complex 1[NiIIL]0, the octaazamacrocyclic ligand is grossly unsaturated (π-conjugated), while in the second 1[NiIILH]2+ one, the macrocycle is saturated with hydrogens. One and two-electron reductions are described using Mulliken population analysis, quantum theory of atoms in molecules, localized orbitals, and domain averaged fermi holes, including the characterization of the Ni-CCO2 bond and the oxidation state of the central Ni atom. It was found that in the [NiLH] complex, the central atom is reduced to Ni0 and/or NiI and is thus able to bind CO2 via a single σ bond. In addition, the two-electron reduced 3[NiL]2− species also shows an affinity forwards CO2.

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