Multicomponent Density Functional Theory: Impact of Nuclear Quantum Effects on Proton Affinities and Geometries

2017 ◽  
Vol 8 (15) ◽  
pp. 3488-3493 ◽  
Author(s):  
Kurt R. Brorsen ◽  
Yang Yang ◽  
Sharon Hammes-Schiffer
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Quantum Effects ◽  
Proton Affinities ◽  
Functional Theory ◽  
Nuclear Quantum Effects

scholarly journals Molecular dynamics with constrained nuclear electronic orbital density functional theory: Accurate vibrational spectra from efficient incorporation of nuclear quantum effects

2021 ◽  
Author(s):  
Xi Xu ◽  
Zehua Chen ◽  
Yang Yang
Keyword(s):  
Molecular Dynamics ◽  
Density Functional Theory ◽  
Vibrational Spectra ◽  
Density Functional ◽  
Molecular Simulations ◽  
Quantum Effects ◽  
Functional Theory ◽  
Chemical And Biological Systems ◽  
Nuclear Quantum Effects ◽  
Orbital Density

Nuclear quantum effects play a crucial role in many chemical and biological systems involving hydrogen atoms yet are difficult to include in practical molecular simulations. In this Letter, we combine our recently developed methods of constrained nuclear-electronic orbital density functional theory (cNEO-DFT) and constrained minimized energy surface molecular dynamics (CMES-MD) to create a new method for accurately and efficiently describing nuclear quantum effects in molecular simulations. Using this new method, dubbed cNEO-MD, the vibrational spectra of a set of small molecules are calculated and compared with those from conventional ab initio molecular dynamics (AIMD) as well as from experiments. With the same formal scaling, cNEO-MD greatly outperforms AIMD in describing the vibrational modes with significant hydrogen motion characters, demonstrating the promise of cNEO-MD for simulating chemical and biological systems with significant nuclear quantum effects.

scholarly journals Protonated heterocyclic derivatives of cyclopropane and cyclopropanone: classical species, alternate sites, and ring fragmentation

2015 ◽  
Vol 93 (7) ◽  
pp. 708-714 ◽  
Author(s):  
Margarida S. Miranda ◽  
Darío J.R. Duarte ◽  
Joaquim C.G. Esteves da Silva ◽  
Joel F. Liebman
Keyword(s):  
Density Functional Theory ◽  
Gas Phase ◽  
Density Functional ◽  
Computational Study ◽  
Basis Set ◽  
Proton Affinities ◽  
Functional Theory ◽  
Heterocyclic Derivatives ◽  
Gas Phase Basicities ◽  
Derivatives Of

A computational study has been performed for protonated oxygen- or nitrogen-containing heterocyclic derivatives of cyclopropane and cyclopropanone. We have searched for the most stable conformations of the protonated species using density functional theory with the B3LYP functional and the 6-31G(2df,p) basis set. More accurate enthalpy values were obtained from G4 calculations. Proton affinities and gas-phase basicities were accordingly derived.

A DFT study of thymine and its tautomers

2009 ◽  
Vol 87 (2) ◽  
pp. 406-415 ◽  
Author(s):  
Dongsheng Jiao ◽  
Hongyan Wang ◽  
Yanlan Zhang ◽  
Yu Tang
Keyword(s):  
Experimental Data ◽  
Density Functional Theory ◽  
Ionization Potential ◽  
Density Functional ◽  
The Other ◽  
Basis Sets ◽  
Electron Affinities ◽  
Proton Affinities ◽  
Functional Theory ◽  
Theoretical Results

The structures and the relative energies of six possible tautomers of the thymine base have been studied by density functional theory (DFT) using the B3LYP and BP86 functionals. The keto-thymine (T1) is predicted to be the most stable thymine tautomer, which is consistent with the other theoretical results and experimental data. The corresponding thymine cations and anions are studied using the same level of theory with double-ζ plus polarization and diffuse functions (DZP++) basis sets. The ionization potentials (IPs), the electron affinities (EAs), and proton affinities (PAs) for different protonation sites in thymine base are obtained. T1 has the largest ionization potential and the lowest proton affinity among all the considered thymine tautomers.

Effects of the Supercell's Size on Muon Positions Calculations of La2CuO4

2019 ◽  
Vol 966 ◽  
pp. 465-470 ◽  
Author(s):  
Muhammad Redo Ramadhan ◽  
Irwan Ramli ◽  
Muhamad Darwis Umar ◽  
Suci Winarsih ◽  
Dita Puspita Sari ◽  
...  
Keyword(s):  
Experimental Data ◽  
Density Functional Theory ◽  
Density Functional ◽  
Quantum Effects ◽  
Dipolar Interaction ◽  
Functional Theory ◽  
Electronic Spin ◽  
The Density Functional Theory ◽  
Dipolar Fields

The outcome of the density functional theory (DFT) technique within the supercell's framework of La2CuO4 (LCO) are reported. We evaluatedlocal dipolar fields of muon's position inside LCO assuming dipolar interaction is occurred by varying the supercell's size. We found out that the field on proposed muon's trapping positions were known to be not affected so much by supercell's size and still fairly larger than the experimental data. Our results suggest that the inclusion of quantum effects of implanted muon and the electronic spin are required to explain experimental data.

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