Theoretical study of the geometrical and electronic properties of Be2Mg+ n (n = 1–11) clusters

2019 ◽  
Vol 9 (7) ◽  
pp. 778-785 ◽  
Author(s):  
Ben-Chao Zhu ◽  
Zhang Yu ◽  
Wang Ping ◽  
Lu Zeng ◽  
Shuai Zhang

By using Density Functional Theory (DFT) method at the B3LYP/6-311G level, the structures, stabilities, and electronic properties of cationic Be2Mg+ n (n = 1–11) clusters have been systematically studied. The optimized geometry show that the ground state structures of cationic Be2Mg+ n (n = 1–11) clusters favor 3D structures except n = 1, 2. Furthermore, the average binding energy E b, the second-order energy differences Δ2E, the fragmentation energy Ef and the HOMO-LUMO energy Egap of the ground state of cationic Be2Mg– n (n = 1–11) clusters are calculated, the final results indicate that Be2Mg+6 and Be2Mg+9 clusters have a higher stability than other clusters. Additionally, the NCP, NEC and Mulliken population analysis reveal that the charges in cationic Be2Mg+ n (n = 1–11) clusters transfer from Mg atom to Be atoms, and strong sp hybridizations are presented in Be atoms of Be2Mg+ n clusters. Finally, the polarizability analysis indicates that the nuclei and electronic clouds of clusters are affected by external field with the increase of cluster size.

2016 ◽  
Vol 24 (04) ◽  
pp. 1750049 ◽  
Author(s):  
JUN ZHU ◽  
XIU-RONG ZHANG ◽  
PEI-YING HUO ◽  
ZHI-CHENG YU

The structure stability and electronic properties of CumConCO ([Formula: see text]–7) clusters have been systematically investigated using density functional theory (DFT) within the generalized gradient approximation (GGA). The results indicate that the ground state structures of CumConCO clusters obtained by adsorbing CO molecules on the top sites of stable CumConclusters with C atoms and CO molecules have been activated during adsorption process. Cu2CO, CuCoCO, Cu3CoCO, Co4CO, Cu4CoCO and Cu3Co3CO clusters are stronger than other ground state clusters in thermodynamic stability. Cu2CO, Cu4CO and Cu6CO clusters show stronger chemical stability; Co2CO, Co4CO, Cu5CoCO, Cu3Co3CO, Cu2Co5CO and Co7CO clusters show better propensity to adsorb CO for these clusters have larger adsorption energies; Electronic states of Cu2Co3CO, CuCo4CO, Co5CO, Cu4Co3CO, Cu3Co4CO, CuCo6CO and Co7CO clusters are mainly influenced by those of 3d orbitals in Co and Cu atoms, the contribution to total magnetic moments of these clusters comes mainly from Co atoms and these clusters have high magnetism.


2018 ◽  
Vol 64 (6) ◽  
pp. 634 ◽  
Author(s):  
Luis Alberto Desales Guzmán ◽  
Juan Horacio Pacheco Sánchez ◽  
Frank Jhonatan Isidro Ortega ◽  
Genoveva García Rosales

We computationally investigate the hydrogen storage properties of C12 carbyne structure decorated with one and up to six calcium (Ca) atoms adsorbed to outer surface. The calculations are carried out by density functional theory DFT with the generalized gradient approximation PW91 (Perdew and Wang) as implemented in the modeling and simulation Materials Studio software. Dmol3 is used to calculate, total energies, charge density HOMO-LUMO and Mulliken population analysis. Based on these results, up to six H2 molecules per Ca atom can be physisorbed with an average binding energy of 0.1272 eV per H2 molecule. The study is extended to a system with six calcium atoms, which can adsorb up to 36 H2 molecules. This leads to 15.87 weight percentage (wt %) for the gravimetric hydrogen storage capacity. According to these results, the calcium-coated carbyne C12 structure is a good candidate for hydrogen storage with application to fuel cells.


2018 ◽  
Vol 33 (1) ◽  
pp. 71
Author(s):  
Ali Hashem Essa ◽  
A. F. Jalbout

The structural and electronic properties of 1-(5-Hydroxymethyl - 4 –[ 5 – (5-oxo-5-piperidin- 1 -yl-penta- 1,3 -dienyl)-benzo [1,3] dioxol- 2 -yl]- tetrahydro -furan-2 -yl)-5-methy l-1Hpyrimidine-2,4dione (AHE) molecule have been investigated theoretically by performing density functional theory (DFT), and semi empirical molecular orbital calculations. The geometry of the molecule is optimized at the level of Austin Model 1 (AM1), and the electronic properties and relative energies of the molecules have been calculated by density functional theory in the ground state. The resultant dipole moment of the AHE molecule is about 2.6 and 2.3 Debyes by AM1 and DFT methods respectively, This property of AHE makes it an active molecule with its environment, that is AHE molecule may interacts with its environment strongly in solution.


Minerals ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 450 ◽  
Author(s):  
Zhang ◽  
Xu ◽  
Hu ◽  
He ◽  
Tian ◽  
...  

A scientific and rigorous study on the adsorption behavior and molecular mechanism of collector sodium oleate (NaOL) on a Ca2+-activated hydroxylated α-quartz surface was performed through experiments and density functional theory (DFT) simulations. The rarely reported hydroxylation behaviors of water molecules on the α-quartz (101) surface were first innovatively and systematically studied by DFT calculations. Both experimental and computational results consistently demonstrated that the adsorbed calcium species onto the hydroxylated structure can significantly enhance the adsorption of oleate ions, resulting in a higher quartz recovery. The calculated adsorption energies confirmed that the adsorbed hydrated Ca2+ in the form of Ca(H2O)3(OH)+ can greatly promote the adsorption of OL− on hydroxylated quartz (101). In addition, Mulliken population analysis together with electron density difference analysis intuitively illustrated the process of electron transfer and the Ca-bridge phenomenon between the hydroxylated surface and OL− ions. This work may offer new insights into the interaction mechanisms existing among oxidized minerals, aqueous medium, and flotation reagents.


Author(s):  
Xing-Chen Yan ◽  
Yu-Hua Fan ◽  
Cai-Feng Bi ◽  
Xia Zhang ◽  
Zhong-Yu Zhang

The contributions of the amino and imino resonance forms to the ground-state structures of 2-amino-4-methylpyridinium nitrate, C6H9N2+·NO3−, and the previously reported 2-amino-5-methylpyridinium nitrate [Yan, Fan, Bi, Zuo & Zhang (2012).Acta Cryst.E68, o2084], were studied using a combination of IR spectroscopy, X-ray crystallography and density functional theory (DFT). The results show that the structures of 2-amino-4-methylpyridine and 2-amino-5-methylpyridine obtained upon protonation are best described as existing largely in the imino resonance forms.


2015 ◽  
Vol 29 (23) ◽  
pp. 1550163
Author(s):  
W. L. Guo ◽  
L. L. Zhang ◽  
M. Luo ◽  
X. R. Zhang

Structures and stabilities of [Formula: see text] clusters have been systematically studied via using density functional theory (DFT) with generalized gradient approximation (GGA). The calculations show that the stable configurations of [Formula: see text] are such structures with one N atom bonded to the external of the basic constructions consisting of Os atoms. Meanwhile, [Formula: see text] clusters [Formula: see text] represent “magic number” effect, and 8 is the magic number. Additionally, the ground-state structures of [Formula: see text] clusters have the best stability, while that of [Formula: see text] cluster possesses the worst stability. The result of the study on the ionization potential (IP) and the electron affinity (EA) shows that there are not topological differences among the configurations of [Formula: see text][Formula: see text] clusters.


2018 ◽  
Vol 32 (20) ◽  
pp. 1850209
Author(s):  
Zhicheng Yu ◽  
Xiurong Zhang ◽  
Kun Gao ◽  
Peiying Huo

Geometric and electronic structures of W[Formula: see text]Cu[Formula: see text]H2 (m + n [Formula: see text] 7) clusters have been systematically calculated by density functional theory (DFT) at the generalized gradient approximation (GGA) level for ground-state structures. For all W–Cu clusters, H atoms prefer to attach to W atoms in this system during adsorption. And more electrons transfer from H atom to W atom with the growth of the size of the cluster which benefits the hydrogen storage. Analysis of stability properties and electronic properties shows that hydrogen adsorption and dissociation process take place more efficiently at the W2Cu3H2 cluster than the others. Due to high thermodynamic stability and adsorption energy of W5CuH2 cluster among W[Formula: see text]Cu[Formula: see text]H2 (m + n [Formula: see text] 7) clusters, W5Cu is more suitable for hydrogen storage.


Author(s):  
Sarah Amara ◽  
Noureddine Tchouar ◽  
Salah Belaidi

In the present paper we have a focus in a study of theoretical characterization of three double headed acyclo-C-nucleosides, which are a recent target of experimental studies. The structural and electronic properties of double headed acyclo-C-nucleosides, 1,4-bis (3-mercapto-1H-1,2,4-triazol-5-yl) butane-1,2,3,4-tetrol, 1,4-bis (4-amino-5-mercapto-4H-1,2,4-triazol-3-yl) butane-1,2,3,4-tetrol and 5,5'-(1,2,3,4-tetrahydroxybutane-1,4-diyl) bis (1,3,4-oxadiazole-2(3H)-thione), have been investigated theoretically by performing semi-empirical molecular orbital, ab initio Hartree-Fock (HF) and Density Functional Theory (DFT) calculations. Geometries of the three molecules are optimized at the level of Austin Model 1 (AM1). The electronic properties and relative energies of the molecules have been calculated by HF and DFT in the ground state.


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