The structure of the CC1n− (n = 1–4) anions and electronic affinities of the corresponding neutrals

1991 ◽  
Vol 69 (6) ◽  
pp. 993-999 ◽  
Author(s):  
G. L. Gutsev ◽  
Tom Ziegler
Keyword(s):  
Density Functional ◽  
Function Theory ◽  
Geometry Optimization ◽  
Full Geometry Optimization ◽  
Neutral Species ◽  
Geometrical Structures ◽  
Functional Theory ◽  
Key Words Density ◽  
Singly Charged ◽  
First Ionization Potential

Electronic and geometrical structures for the ground states of the singly charged anions CCln−, n = 1–4, and Clm−, m = 2, 3, as well as the corresponding neutral species have been studied by Approximate Density Functional Theory (DFT). A full geometry optimization has been carried out on both anionic and neutral species. Vertical and adiabatic electron affinities were evaluated for the neutral species along with an estimate of the first ionization potential (FIP) for the anions. A discussion is given of the different dissociation channels for CCl4−. It follows from the present set of calculations that the anion CCl4− is non-rigid with a global minima corresponding to an elongated tetrahedron of C3v symmetry. Key words: Density Function Theory, electronic affinities.

scholarly journals Computational Study of the Electron Spectra of Vapor-Phase Indole and Four Azaindoles

Molecules ◽  
2021 ◽  
Vol 26 (7) ◽  
pp. 1947
Author(s):  
Delano P. Chong
Keyword(s):  
Density Functional Theory ◽  
Vapor Phase ◽  
Density Functional ◽  
Computational Study ◽  
Geometry Optimization ◽  
The Other ◽  
Functional Theory ◽  
Electron Spectra

After geometry optimization, the electron spectra of indole and four azaindoles are calculated by density functional theory. Available experimental photoemission and excitation data for indole and 7-azaindole are used to compare with the theoretical values. The results for the other azaindoles are presented as predictions to help the interpretation of experimental spectra when they become available.

Density functional theory investigation of the effect of axial coordination and annelation on the absorption spectroscopy of nickel(II) and vanadyl porphyrins relevant to bitumen and crude oils

2013 ◽  
Vol 91 (9) ◽  
pp. 872-878 ◽  
Author(s):  
Stanislav R. Stoyanov ◽  
Cindy-Xing Yin ◽  
Murray R. Gray ◽  
Jeffrey M. Stryker ◽  
Sergey Gusarov ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Polyaromatic Hydrocarbons ◽  
Geometry Optimization ◽  
Soret Band ◽  
Heavy Oils ◽  
Visible Absorption ◽  
Functional Theory ◽  
Axial Coordination ◽  
Td Dft

The vanadium and nickel components in heavy oils and bitumen are important impurities in catalytic processing and form aggregates with other asphaltene components. Metalloporphyrins are commonly analyzed using the characteristic Soret band in the UV–vis absorption spectrum. However, the Soret band of metalloporphyrins in petroleum is broadened and weaker than expected based on the concentration of Ni and V in heavy oils and the extinction coefficients of isolated porphyrins. We hypothesize that the low intensity and broadening of the Soret band could be due to axial coordination of the metal center or fusion (annelation) of aromatic rings on the porphyrin π-system. This hypothesis is examined using the density functional theory for geometry optimization and time-dependent density functional theory (TD-DFT) for calculation of excited states of nickel(II) and vanadyl porphyrins with axially coordinated ligands and annelated polyaromatic hydrocarbons. Predictions of the excited electronic states performed using the tandem of TD-DFT and conductor-like polarizable continuum model of solvation support this hypothesis and provide insight into the extent of Soret band broadening and intensity decrease due to coordination and annelation. These computational results, validated with respect to visible absorption spectra, are important for understanding asphaltene aggregation and spectroscopic characterization and suggest methods for removal of transition metals from heavy oil.

scholarly journals Doping the Buckminsterfullerene by Substitution: Density Functional Theory Studies of C59X (X = B, N, Al, Si, P, Ga, Ge, and As)

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Hongcun Bai ◽  
Wenxin Ji ◽  
Xiangyu Liu ◽  
Liqiong Wang ◽  
Nini Yuan ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Physical Properties ◽  
Density Functional ◽  
Dielectric Constants ◽  
Geometrical Structures ◽  
Functional Theory ◽  
Relative Stabilities ◽  
As Doping ◽  
Quantum Chemistry Calculations ◽  
Heteroatom Substitution

The heterofullerenes C59X (X = B, N, Al, Si, P, Ga, Ge, and As) were investigated by quantum chemistry calculations based on density functional theory. These hybrid cages can be seen as doping the buckminsterfullerene by heteroatom substitution. The geometrical structures, relative stabilities, electronic properties, vibrational frequencies, dielectric constants, and aromaticities of the doped cages were studied systemically and compared with those of the pristine C60cage. It is found that the doped cages with different heteroatoms exhibit various electronic, vibrational, and aromatic properties. These results imply the possibility to modulate the physical properties of these fullerene-based materials by tuning substitution elements.

Investigation, using density function theory, of coverage of the kaolinite (001) surface during hydrogen adsorption

Clay Minerals ◽  
2018 ◽  
Vol 53 (3) ◽  
pp. 393-402 ◽  
Author(s):  
Jian Zhao ◽  
Wei Gao ◽  
Zhi-Gang Tao ◽  
Hong-Yun Guo ◽  
Man-Chao He
Keyword(s):  
Density Functional ◽  
Hydrogen Adsorption ◽  
Function Theory ◽  
Lattice Relaxation ◽  
Electronic Density ◽  
Functional Theory ◽  
Adsorption Sites ◽  
Coverage Dependence ◽  
Hydrogen Molecules ◽  
Wide Range

ABSTRACTKaolinite can be used for many applications, including the underground storage of gases. Density functional theory was employed to investigate the adsorption of hydrogen molecules on the kaolinite (001) surface. The coverage dependence of the adsorption sites and energetics was studied systematically for a wide range of coverage, Θ (from 1/16 to 1 monolayer). The three-fold hollow site is the most stable, followed by the bridge, top-z and top sites. The adsorption energy of H2 decreased with increasing coverage, thus indicating the lower stability of surface adsorption due to the repulsion of neighbouring H2 molecules. The coverage has obvious effects on hydrogen adsorption. Other properties of the H2/kaolinite (001) system, including the lattice relaxation and changes of electronic density of states, were also studied and are discussed in detail.

scholarly journals Distinctive Supramolecular Features of β-Cyclodextrin Inclusion Complexes with Antidepressants Protriptyline and Maprotiline: A Comprehensive Structural Investigation

2021 ◽  
Vol 14 (8) ◽  
pp. 812
Author(s):  
Thammarat Aree
Keyword(s):  
Inclusion Complexes ◽  
Density Functional ◽  
Water Solubility ◽  
Geometry Optimization ◽  
Binding Constants ◽  
Basis Set ◽  
Full Geometry Optimization ◽  
Basis Set Superposition Error ◽  
X Ray ◽  
Molecular Stability

Depression, a global mental illness, is worsened due to the coronavirus disease 2019 (COVID-2019) pandemic. Tricyclic antidepressants (TCAs) are efficacious for the treatment of depression, even though they have more side effects. Cyclodextrins (CDs) are powerful encapsulating agents for improving molecular stability, water solubility, and lessening the undesired effects of drugs. Because the atomic-level understanding of the β-CD–TCA inclusion complexes remains elusive, we carried out a comprehensive structural study via single-crystal X-ray diffraction and density functional theory (DFT) full-geometry optimization. Here, we focus on two complexes lining on the opposite side of the β-CD–TCA stability spectrum based on binding constants (Kas) in solution, β-CD–protriptyline (PRT) 1—most stable and β-CD–maprotiline (MPL) and 2—least stable. X-ray crystallography unveiled that in the β-CD cavity, the PRT B-ring and MPL A-ring are aligned at a nearly perfect right angle against the O4 plane and primarily maintained in position by intermolecular C–H···π interactions. The increased rigidity of the tricyclic cores is arising from the PRT -CH=CH- bridge widens, and the MPL -CH2–CH2- flexure narrows the butterfly angles, facilitating the deepest and shallower insertions of PRT B-ring (1) and MPL A-ring (2) in the distorted round β-CD cavity for better complexation. This is indicated by the DFT-derived complex stabilization energies (ΔEstbs), although the complex stability orders based on Kas and ΔEstbs are different. The dispersion and the basis set superposition error (BSSE) corrections were considered to improve the DFT results. Plus, the distinctive 3D arrangements of 1 and 2 are discussed. This work provides the first crystallographic evidence of PRT and MPL stabilized in the β-CD cavity, suggesting the potential application of CDs for efficient drug delivery.

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 Взаимодействие alpha-частиц keV-энергий с молекулами глицил-лейцина

2021 ◽  
Vol 47 (12) ◽  
pp. 23
Author(s):  
А.А. Басалаев ◽  
А.Г. Бузыкин ◽  
В.В. Кузьмичев ◽  
М.Н. Панов ◽  
А.В. Петров ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Cross Sections ◽  
Density Functional ◽  
Molecular Ions ◽  
Functional Theory ◽  
The Density Functional Theory ◽  
Singly Charged ◽  
Doubly Charged ◽  
First Time ◽  
Fragmentation Processes

Radiation damage to isolated glycyl-leucine (C8H16N2O3) molecules caused by interaction with He2+ ions was studied. For the first time, the relative cross sections of the main processes of changes in the charge state of the collision partners and the relative cross sections of the fragmentation processes of singly and doubly charged molecular ions formed during single collisions of glycyl-leucine molecules with ions have been obtained. The optimized geometry of the molecule and singly charged glycyl-leucine ion was calculated using the density functional theory (DFT).

DENSITY FUNCTIONAL THEORY STUDY OF H2O ADSORPTION AND DISSOCIATION ON Al (111) SURFACE

2013 ◽  
Vol 12 (05) ◽  
pp. 1350035 ◽  
Author(s):  
LIXIA YANG ◽  
XIAOLI LEI ◽  
JUN FENG ◽  
YUXIN ZHANG ◽  
MINGXING LIU
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Catalytic Effect ◽  
Geometry Optimization ◽  
Vacancy Defect ◽  
Hydroxyl Group ◽  
Dissociation Pathway ◽  
Functional Theory ◽  
Lower Activation ◽  
Adsorption And Dissociation

Comparative study about the adsorption and dissociation behaviors of H2O molecule on clean and vacancy defective Al (111) surface was conducted by extensive density functional theory (DFT) calculations, the interaction mechanisms between H2O molecule and Al (111) surface were also figured out. Geometry optimization results indicated that H2O molecule was apt to be adsorbed at top site on these two kinds of surfaces, whereas, the adsorption configurations, the adsorption type and inclination of H2O molecule planes away from the normal were different. The calculated adsorption energies demonstrated that the adsorption of H2O molecule occurred more readily on vacancy defective Al (111) surface. The electron density distribution indicated that the vacancy defect enhanced the interactions between H2O molecule and surface Al atoms. Further analysis of the density of states (DOS) showed that the vacancy defect increased the number of bonding electrons between H2O molecule and surface Al atoms. The detailed exploration of dissociation pathways demonstrated that the dissociation of H2O molecule on these two kinds of surfaces was a two-step process: (1) H2O → H + OH , (2) OH → H + O . However, for each step the dissociation pathway variations on vacancy defective Al (111) surface were different with those on clean Al (111) surface. Compared with the first step, the dissociation of hydroxyl group into O atom and H atom was kinetically difficult. The calculated lower activation energy barriers on vacancy defective Al (111) surface showed that the vacancy defect had catalytic effect for the dissociation of H2O molecule to some extent, especially for the first step.

Sign in / Sign up

Export Citation Format

Share Document