scholarly journals Relative Stability of Small Silver, Platinum, and Palladium Doped Gold Cluster Cations

2019 ◽  
Vol 9 (8) ◽  
pp. 1666 ◽  
Author(s):  
Piero Ferrari ◽  
Ewald Janssens
Keyword(s):  
Density Functional ◽  
Gold Cluster ◽  
Density Functional Theory Calculations ◽  
Functional Theory ◽  
Local Maxima ◽  
Dissociation Energies ◽  
Valence Electrons ◽  
Pd Doping ◽  
The Stability ◽  
Experimental Findings

The stability patterns of single silver, platinum, and palladium atom doped gold cluster cations, MAuN−1+ (M = Ag, Pt, Pd; N = 3–6), are investigated by a combination of photofragmentation experiments and density functional theory calculations. The mass spectra of the photofragmented clusters reveal an odd-even pattern in the abundances of AgAuN−1+, with local maxima for clusters containing an even number of valence electrons, similarly to pure AuN+. The odd-even pattern, however, disappears upon Pt and Pd doping. Computed dissociation energies agree well with the experimental findings for the different doped clusters. The effect of Ag, Pt, and Pd doping is discussed on the basis of an analysis of the density of states of the N = 3–5 clusters. Whereas Ag delocalizes its 5s valence electron in all sizes, this process is size-specific for Pt and Pd.

Targeting complex plutonium oxides by combining crystal chemical reasoning with density-functional theory calculations: the quaternary plutonium oxide Cs2PuSi6O15

2020 ◽  
Vol 56 (66) ◽  
pp. 9501-9504
Author(s):  
Kristen A. Pace ◽  
Vladislav V. Klepov ◽  
Matthew S. Christian ◽  
Gregory Morrison ◽  
Travis K. Deason ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Crystal Growth ◽  
Dft Calculations ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Crystal Chemical ◽  
The Novel ◽  
Functional Theory ◽  
The Stability ◽  
Chemical Reasoning

The stability of the novel Pu(iv) silicate, Cs2PuSi6O15, was predicted from a combination of crystal chemical reasoning and DFT calculations and confirmed by its synthesis via flux crystal growth.

DFT STUDIES ON THE STABILITY OF THE TRANS AND CIS ISOMERS IN THE SQUARE PLANAR PALLADIUM(II) COMPLEXES Pd(I)(PPh3)(η3-XCHC(Ph)CHR) (X = CMe3, CO2Me, P(O)(OMe)2, AND SO2H; R = H, Me)

2008 ◽  
Vol 07 (04) ◽  
pp. 505-515
Author(s):  
LIQIN XUE ◽  
GUOCHEN JIA ◽  
ZHENYANG LIN
Keyword(s):  
Density Functional Theory ◽  
Electronic Properties ◽  
Relative Stability ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Dft Studies ◽  
Functional Theory ◽  
Square Planar ◽  
The Stability ◽  
Cis Isomer

The relative stability of the trans and cis isomers in the square planar palladium(II) complexes Pd ( I )( PPh 3)(η3- XCHC ( Ph ) CHR ) ( X = H , Me , CMe 3, CO 2 Me , P ( O )( OMe )2, and SO 2 H ; R = H , Me ) was investigated with the aid of the B3LYP density functional theory calculations. We examined how the substituents X, with different electronic properties, of the η3-allyl ligands affect the relative stability of the trans and cis isomers. Through the investigation, we were able to explain the trans/cis relative stability derived from the experimentally measured trans/cis isomer ratios in the palladium(II) complexes.

Density Functional Theory Calculations of Properties of the Grain Boundaries in Aluminum

2011 ◽  
Vol 1297 ◽  
Author(s):  
Marek Muzyk ◽  
Krzysztof J. Kurzydlowski
Keyword(s):  
Density Functional Theory ◽  
Grain Boundaries ◽  
Density Functional ◽  
Quantitative Description ◽  
Aluminum Matrix ◽  
Density Functional Theory Calculations ◽  
Functional Theory ◽  
Nano Crystalline ◽  
The Density Functional Theory ◽  
The Stability

ABSTRACTThe Density Functional Theory has been used to analyze an inter-granular segregation of Cu and Mg. The stability of Cu and Mg atoms in the aluminum matrix, intermetallic phases and symmetric twist grain boundaries has been compared. The quantitative description of solubility of Cu and Mg atoms in the nano-crystalline aluminum has been proposed. The calculations have been carried out to investigate the properties of symmetric twist boundaries in aluminum with and without Cu/Mg atoms. The phenomena of are discussed and its effect on the stability of precipitates containing these elements.

scholarly journals Advanced study of hydrogen storage by substitutional doping of Mn and Ti in Mg2Ni phase

2014 ◽  
Vol 5 ◽  
pp. A24 ◽  
Author(s):  
Omar Elkedim ◽  
Liwu Huang ◽  
David Bassir
Keyword(s):  
Density Functional Theory ◽  
Hydrogen Storage ◽  
First Principles ◽  
Density Functional ◽  
Lattice Site ◽  
Density Functional Theory Calculations ◽  
Functional Theory ◽  
Substitutional Doping ◽  
The Stability ◽  
Ti Substitution

The substitutional doping of Mn and Ti in Mg2Ni phase has been investigated by first principles density functional theory calculations. The calculation of enthalpy of formation shows that among the four different lattice sites of Mg(6f), Mg(6i), Ni(3b) and Ni(3d) in Mg2Ni unit cell, the most preferable site of substitution of Mn in Mg2Ni lattice has been confirmed to be Mg(6i) lattice site. The most preferable site of Ti substitution in Mg2Ni lattice is Mg(6i) position and the stability of Ti-doped Mg2Ni decreases with the increase of substitution quantity of Ti for Mg.

scholarly journals Synthesis and Structure Insights of Two Novel Broad-Spectrum Antibacterial Candidates Based on (E)-N′-[(Heteroaryl)methylene]adamantane-1-carbohydrazides

Molecules ◽  
2020 ◽  
Vol 25 (8) ◽  
pp. 1934
Author(s):  
Lamya H. Al-Wahaibi ◽  
Natalia Alvarez ◽  
Olivier Blacque ◽  
Nicolás Veiga ◽  
Aamal A. Al-Mutairi ◽  
...  
Keyword(s):  
Electron Density ◽  
Broad Spectrum ◽  
Light Absorption ◽  
Density Functional ◽  
Pathogenic Fungus ◽  
Thiophene Ring ◽  
Density Functional Theory Calculations ◽  
X Ray Diffraction ◽  
Functional Theory ◽  
The Stability

Two new N′-heteroarylidene-1-carbohydrazide derivatives, namely; E-N′-[(pyridine-3-yl)methylidene]adamantane-1-carbohydrazide (1) and E-N′-[(5-nitrothiophen-2-yl)methylidene]adamantane-1-carbohydrazide (2), were produced via condensation of adamantane-1-carbohydrazide with the appropriate heterocyclic aldehyde. Both compounds were chemically and structurally characterized by 1H-NMR, 13C-NMR, infrared and UV-vis spectroscopies, and single crystal X-ray diffraction. The study was complemented with density functional theory calculations (DFT). The results show an asymmetrical charge distribution in both compounds, with the electron density accumulated around the nitrogen and oxygen atoms, leaving the positive charge surrounding the N-H and C-H bonds in the hydrazine group. Consequently, the molecules stack in an antiparallel fashion in the crystalline state, although the contribution of the polar contacts to the stability of the lattice is different for 1 (18%) and 2 (42%). This difference affects the density and symmetry of their crystal structures. Both molecules show intense UV-Vis light absorption in the range 200–350 nm (1) and 200–500 nm (2), brought about by π → π* electronic transitions. The electron density difference maps (EDDM) revealed that during light absorption, the electron density flows within the π-delocalized system, among the pyridyl/thiophene ring, the nitro group, and the N′-methyleneacetohydrazide moiety. Interestingly, compounds 1 and 2 constitute broad-spectrum antibacterial candidates, displaying potent antibacterial activity with minimal inhibitory concentration (MIC) values around 0.5–2.0 μg/mL. They also show weak or moderate antifungal activity against the yeast-like pathogenic fungus Candida albicans.

Density functional theory study of transition metals doped B80 fullerene

2014 ◽  
Vol 13 (06) ◽  
pp. 1450050 ◽  
Author(s):  
Jianguang Wang ◽  
Li Ma ◽  
Yanhua Liang ◽  
Meiling Gao ◽  
Guanghou Wang
Keyword(s):  
Density Functional Theory ◽  
Outer Surface ◽  
Density Functional ◽  
Formation Energy ◽  
Magnetic Moments ◽  
Density Functional Theory Calculations ◽  
Density Functional Theory Study ◽  
Functional Theory ◽  
Energy Gaps ◽  
The Stability

Density functional theory calculations have been carried out to investigate 3d, Pd and Pt transition metal (TM) atoms exohedrally and endohedrally doped B 80 fullerene. We find that the most preferred doping site of the TM atom gradually moves from the outer surface ( TM = Sc ), to the inner surface ( TM = Ti and V ) and the center ( TM = Cr , Mn , Fe and Zn ), then to the outer surface ( TM = Co , Ni , Cu , Pd , and Pt ) again with the TM atom varying from Sc to Pt . From the formation energy calculations, we find that doping TM atom can further improve the stability of B 80 fullerene. The magnetic moments of doped V , Cr , Mn , Fe , Co and Ni atoms are reduced from their free-atom values and other TM atoms are completely quenched. Charge transfer and hybridization between 4s and 3d states of TM and 2s and 2p states of B were observed. The energy gaps of TM @ B 80 are usually smaller than that of the pure B 80. Endohedrally doped B 80 fullerene with two Mn and two Fe atoms were also considered, respectively. It is found that the antiferromagnetic (AFM) state is more energetically favorable than the ferromagnetic (FM) state for Mn 2- and Fe 2@ B 80. The Mn and Fe atoms carry the residual magnetic moments of ~ 3 μB and 2 μB in the AFM states.

Structure of Small Gold Clusters with Si Doping Using DFT (AunSi, n=1-10, 19)

2013 ◽  
Vol 24 ◽  
pp. 203-212 ◽  
Author(s):  
Priyanka ◽  
Sumali Bansal ◽  
Keya Dharamvir
Keyword(s):  
Density Functional ◽  
Gold Cluster ◽  
Chemical Reactivity ◽  
Gold Clusters ◽  
Functional Theory ◽  
Si Doped ◽  
Silicon Doped ◽  
The Stability ◽  
Almost All ◽  
Homo Lumo

The structures of silicon doped gold clusters AunSi (n = 1-10 and 19) have been investigated using first principle calculations based on density functional theory (DFT). Calculations indicate that the stability of a gold cluster increases with the introduction of a Si atom. In all the low lying geometries, Si prefers peripheral positions. For every ground state configuration with n > 3 (n = 6 and 9 being exceptions) Si has tetra-coordination. In almost all of the tetra coordinated geometries the coordination unit including Si, is in the form of a square pyramid with gold atoms forming the square base. Electronic properties such as HOMO-LUMO gap, ionization potential and electron affinity have also been calculated and support the relative stability of clusters with even n. The study of Au20 cage doped with Si atom has been done .Similar to smaller Si doped gold clusters; the Si atom prefers an exohedral position. The doping of Si atom has enhanced the stability and chemical reactivity of Au20 cluster.

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