Relative energy of the high-(T2g5) and low-(A1g1) spin states of [Fe(H2O)6]2+, [Fe(NH3)6]2+, and [Fe(bpy)3]2+: CASPT2 versus density functional theory

2006 ◽  
Vol 125 (12) ◽  
pp. 124303 ◽  
Author(s):  
Kristine Pierloot ◽  
Steven Vancoillie
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Relative Energy ◽  
Spin States ◽  
Functional Theory

scholarly journals A Density Functional Theory Investigation of the Reaction of Water with Ce2O-

2020 ◽  
Author(s):  
Hassan Harb ◽  
Hrant Hratchian
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Function Theory ◽  
Practical Importance ◽  
Density Function Theory ◽  
Catalyst Design ◽  
Reaction Pathways ◽  
Spin States ◽  
Functional Theory ◽  
Energy Science

<div>Cerium suboxide clusters have been shown to react with water to yield H<sub>2</sub>. Since reactions of metal oxides with water are of great fundamental and practical importance in energy science, detailed study of this reaction can provide new key knowledge for future catalyst design. Using density function theory calculations, we identified and report complete reaction pathways for two spin-states of Ce<sub>2</sub>O<sup>–</sup> reacting with H<sub>2</sub>O. Additionally, examining the molecular orbitals of initial and final cerium oxide clusters, we found that metal d electrons facilitate the reduction of water. This work provides new understanding of this reaction and insights to the reactivity enhancements for cerium-doped surfaces.</div>

scholarly journals Assessing Density Functional Theory Approaches for Predicting the Structure and Relative Energy of Salicylideneaniline Molecular Switches in the Solid State

2017 ◽  
Vol 121 (12) ◽  
pp. 6898-6908 ◽  
Author(s):  
Jean Quertinmont ◽  
Andrea Carletta ◽  
Nikolay A. Tumanov ◽  
Tom Leyssens ◽  
Johan Wouters ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Solid State ◽  
Density Functional ◽  
Molecular Switches ◽  
Relative Energy ◽  
Functional Theory

Density functional theory study of bis(imino) N-heterocyclic carbene iron(II) complexes

2014 ◽  
Vol 92 (10) ◽  
pp. 925-931 ◽  
Author(s):  
Jameel Al Thagfi ◽  
Gino G. Lavoie
Keyword(s):  
Density Functional Theory ◽  
Electron Density ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Iron Complexes ◽  
Relative Energy ◽  
Iron Complex ◽  
Geometrical Parameters ◽  
Functional Theory ◽  
Imine Group

Density functional theory calculations at the B3LYP/DGDZVP and UB3LYP/TZVP levels were performed on 1,3-bis[1-(2,6-dimethylphenylimino)ethyl]imidazolium and on the corresponding imidazol-2-ylidene iron(II) dichloride complex, respectively. The resulting geometrical parameters of the optimized structures were in good agreement with previously reported X-ray structures. The ground state for the high-spin (quintet multiplicity) iron complex is 82.4 kJ/mol lower in energy compared to the low-spin (triplet) configuration, in agreement with magnetic susceptibility measurements. Further calculations were carried out on related benzimidazol-2-ylidene and pyrimidin-2-ylidene ligands and on the corresponding iron complexes to gain insight into their electronic properties and reactivities. The energy of the highest occupied and lowest unoccupied molecular orbitals of all three carbenes suggests that the pyrimidin-2-ylidene and the benzimidazol-2-ylidene are the best σ-donor and best π-acceptor, respectively. Using those results, the metal center in the pyrimidin-2-ylidene iron dichloride complex was predicted to bear the highest electron density. This was supported by the high relative energy of its highest occupied molecular orbital compared to that of the corresponding imidazole-2-ylidene and benzimidazol-2-ylidene iron complexes. The electrostatic potential maps of all three metal complexes furthermore indicated a marked decrease in electron density for the coordinated imine group, supporting a greater reactivity towards nucleophiles.

Ab Initio Theoretical Studies of Relative Stabilities and IR Spectrum of 5-Methylcytosine Tautomers

2003 ◽  
Vol 2003 (4) ◽  
pp. 195-199 ◽  
Author(s):  
Lida Ghassemzadeh ◽  
Majid Monajjemi ◽  
Karim Zare
Keyword(s):  
Density Functional Theory ◽  
Gas Phase ◽  
Density Functional ◽  
Relative Energy ◽  
Theoretical Studies ◽  
Functional Theory ◽  
Relative Stabilities ◽  
B3lyp Method ◽  
Wide Range ◽  
Good Agreement

The structure and relative energies of the tautomers of 5-methylcytosine in the gasphase and in different solvents are predicted using MP2 and density functional theory methods. The order of stability for these tautomers is C3>C1>C2>C4>C5>C6 calculated by MP2 and C1>C3>C2>C4>C5>C6 calculated by the B3LYP method. Relative energy calculations are performed in wide range of solvent dielectrics and in all solvents the oxo-amino C1 is predicted as the most stable tautomer. The infrared spectra of two dominant tautomers are calculated in the gas phase using HF and density functional theory. Good agreement between calculated (DFT) and experimental harmonic vibrational frequencies is found.

scholarly journals Nuclear inelastic scattering and density functional theory studies of a one-dimensional spin crossover [Fe(1,2,4-triazole)2(1,2,4-triazolato)](BF4) molecular chain

2017 ◽  
Vol 19 (29) ◽  
pp. 18880-18889 ◽  
Author(s):  
Kevin Jenni ◽  
Lena Scherthan ◽  
Isabelle Faus ◽  
Jennifer Marx ◽  
Cornelius Strohm ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Inelastic Scattering ◽  
Density Functional ◽  
Spin Crossover ◽  
Nuclear Inelastic Scattering ◽  
Spin States ◽  
Functional Theory ◽  
Vibrational Dynamics ◽  
One Dimensional ◽  
High Spin States

NIS experiments display the vibrational dynamics of the low- and high-spin states of the 1D spin crossover compound [Fe(trzH)2(trz)](BF4) (1).

scholarly journals A Density Functional Theory Investigation of the Reaction of Water with Ce2O-

2020 ◽  
Author(s):  
Hassan Harb ◽  
Hrant Hratchian
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Function Theory ◽  
Practical Importance ◽  
Density Function Theory ◽  
Catalyst Design ◽  
Reaction Pathways ◽  
Spin States ◽  
Functional Theory ◽  
Energy Science

<div>Cerium suboxide clusters have been shown to react with water to yield H<sub>2</sub>. Since reactions of metal oxides with water are of great fundamental and practical importance in energy science, detailed study of this reaction can provide new key knowledge for future catalyst design. Using density function theory calculations, we identified and report complete reaction pathways for two spin-states of Ce<sub>2</sub>O<sup>–</sup> reacting with H<sub>2</sub>O. Additionally, examining the molecular orbitals of initial and final cerium oxide clusters, we found that metal d electrons facilitate the reduction of water. This work provides new understanding of this reaction and insights to the reactivity enhancements for cerium-doped surfaces.</div>

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