1
|
Banerjee S, Ash T, Debnath T, Das AK. Dual modification to stabilize Non-IPR C 72 fullerene: A new theoretical strategy. J Mol Graph Model 2022; 117:108289. [PMID: 35964364 DOI: 10.1016/j.jmgm.2022.108289] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2022] [Revised: 07/21/2022] [Accepted: 08/01/2022] [Indexed: 01/14/2023]
Abstract
The stabilization of non-IPR fullerenes for their isolation and characterization is an area of recent interest. In the present study, we have explored the stabilization techniques of C72 isomers via endo and exo-modifications and finally approached dual modification. A total of four isomers of C72 have been considered in this study; among them, one is IPR derivative (1), and the rest are non-IPR derivatives with one (2) and two (3 and 4) fused pentagon rings. First, we have studied the endohedral modification by encapsulating one and two La atoms in the C72 cavity. Secondly, we have exohedrally modified the C72 isomers via chlorination by adding four and eight chlorides, respectively. Our final approach is to study the dual modification, where we have implemented both endo exo-modifications together. This dual modification can be achieved in two ways: exo followed by endo and endo followed by exo. For each modification, the relative stability of every modified C72 derivative has been checked by calculating the relative energy with respect to the most stable modified analogue. To find out whether these modifications are energetically feasible or not, we have calculated the binding energy of each modified C72 isomer. The binding energy calculation reveals that the encapsulation and exo-modification techniques are good enough to stabilize the non-IPR C72 derivatives. Moreover, the effectiveness of dual modification has also been established from the enhanced binding energy compared to either endo- or exo-modification. We have also studied the NPA charges on the encapsulated La atoms for each endo- and dual-modified C72 derivative. Furthermore, the AIM study has also been perceived to find out the interaction between the La atom and the fullerene cages for both mono- and di-encapsulated fullerene derivatives and also between La-La centres for di-encapsulated derivatives. Overall, the present theoretical study will provide an idea about the stability of the modified C72 derivatives, which will help the experimentalists to design new strategies for synthesizing modified non-IPR fullerene derivatives that have vast applications in the medicinal and industrial fields.
Collapse
Affiliation(s)
- Soumadip Banerjee
- School of Mathematical & Computational Sciences, Indian Association for the Cultivation of Science, Jadavpur, Kolkata, 700032, India
| | - Tamalika Ash
- School of Mathematical & Computational Sciences, Indian Association for the Cultivation of Science, Jadavpur, Kolkata, 700032, India
| | - Tanay Debnath
- School of Mathematical & Computational Sciences, Indian Association for the Cultivation of Science, Jadavpur, Kolkata, 700032, India.
| | - Abhijit K Das
- School of Mathematical & Computational Sciences, Indian Association for the Cultivation of Science, Jadavpur, Kolkata, 700032, India.
| |
Collapse
|
2
|
Balasubramanian K. Topological Peripheral Shapes and Distance-Based Characterization of Fullerenes C 20-C 720: Existence of Isoperipheral Fullerenes. Polycycl Aromat Compd 2022. [DOI: 10.1080/10406638.2020.1802303] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
|
3
|
Hu A, Chan NWC, Dunlap BI. Orbital angular momentum eigenfunctions for fast and numerically stable evaluations of closed-form pseudopotential matrix elements. J Chem Phys 2017; 147:074102. [PMID: 28830154 DOI: 10.1063/1.4985874] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The computation of s-type Gaussian pseudopotential matrix elements involving low powers of the distance from the pseudopotential center using Gaussian orbitals can be reduced to familiar integrals. They may be directly expressed as either simple three-center overlap integrals for even powers of the radial distance from the pseudopotential center or related to the three-center nuclear integrals of a Gaussian charge distribution for odd powers. Orbital angular momentum about each atom is added to these integrals by solid-harmonic differentiation with respect to its center. The solid-harmonic addition theorem allows all the integrals to be factored into products of invariant one-dimensional integrals involving the Gaussian exponents and angular factors that contain the azimuthal quantum numbers but are independent of all Gaussian exponents. Precomputing the angular factors allow looping over all Gaussian exponents about the three centers. The fact that solid harmonics are eigenstates of angular momentum removes the singularities seen in previous treatments of pseudopotential matrix elements.
Collapse
Affiliation(s)
- Anguang Hu
- Defence R&D Canada-Suffield Research Centre, P.O. Box 4000, Station Main, Medicine Hat, Alberta T1A 8K6, Canada
| | - Nora W C Chan
- Defence R&D Canada-Suffield Research Centre, P.O. Box 4000, Station Main, Medicine Hat, Alberta T1A 8K6, Canada
| | - Brett I Dunlap
- Code 6189, Chemistry Division, U.S. Naval Research Laboratory, Washington, D.C. 30375-5342, USA
| |
Collapse
|
4
|
Sinitsa AS, Chamberlain TW, Zoberbier T, Lebedeva IV, Popov AM, Knizhnik AA, McSweeney RL, Biskupek J, Kaiser U, Khlobystov AN. Formation of Nickel Clusters Wrapped in Carbon Cages: Toward New Endohedral Metallofullerene Synthesis. NANO LETTERS 2017; 17:1082-1089. [PMID: 28075593 DOI: 10.1021/acs.nanolett.6b04607] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Despite the high potential of endohedral metallofullerenes (EMFs) for application in biology, medicine and molecular electronics, and recent efforts in EMF synthesis, the variety of EMFs accessible by conventional synthetic methods remains limited and does not include, for example, EMFs of late transition metals. We propose a method in which EMF formation is initiated by electron irradiation in aberration-corrected high-resolution transmission electron spectroscopy (AC-HRTEM) of a metal cluster surrounded by amorphous carbon inside a carbon nanotube serving as a nanoreactor and apply this method for synthesis of nickel EMFs. The use of AC-HRTEM makes it possible not only to synthesize new, previously unattainable nanoobjects but also to study in situ the mechanism of structural transformations. Molecular dynamics simulations using the state-of-the-art approach for modeling the effect of electron irradiation are performed to rationalize the experimental observations and to link the observed processes with conditions of bulk EMF synthesis.
Collapse
Affiliation(s)
- Alexander S Sinitsa
- National Research Centre "Kurchatov Institute" , Kurchatov Square 1, Moscow 123182, Russia
| | - Thomas W Chamberlain
- Institute of Process Research and Development, School of Chemistry, University of Leeds , Leeds LS2 9JT, United Kingdom
| | - Thilo Zoberbier
- Group of Electron Microscopy of Materials Science, Central Facility for Electron Microscopy, Ulm University , Albert Einstein Allee 11, Ulm 89081, Germany
| | - Irina V Lebedeva
- Nano-Bio Spectroscopy Group and ETSF, Universidad del País Vasco, CFM CSIC-UPV/EHU , San Sebastian 20018, Spain
| | - Andrey M Popov
- Institute for Spectroscopy of Russian Academy of Sciences , Fizicheskaya Street 5, Troitsk, Moscow 108840, Russia
| | - Andrey A Knizhnik
- National Research Centre "Kurchatov Institute" , Kurchatov Square 1, Moscow 123182, Russia
- Kintech Lab Ltd. , 3rd Khoroshevskaya Street 12, Moscow 123298, Russia
| | - Robert L McSweeney
- School of Chemistry, University of Nottingham , University Park, Nottingham NG7 2RD, United Kingdom
| | - Johannes Biskupek
- Group of Electron Microscopy of Materials Science, Central Facility for Electron Microscopy, Ulm University , Albert Einstein Allee 11, Ulm 89081, Germany
| | - Ute Kaiser
- Group of Electron Microscopy of Materials Science, Central Facility for Electron Microscopy, Ulm University , Albert Einstein Allee 11, Ulm 89081, Germany
| | - Andrei N Khlobystov
- School of Chemistry, University of Nottingham , University Park, Nottingham NG7 2RD, United Kingdom
| |
Collapse
|
5
|
Zope RR, Bhusal S, Basurto L, Baruah T, Jackson K. Site specific atomic polarizabilities in endohedral fullerenes and carbon onions. J Chem Phys 2015; 143:084306. [DOI: 10.1063/1.4928079] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Rajendra R. Zope
- Department of Physics, The University of Texas at El Paso, El Paso, Texas 79958, USA
- Computational Science Program, The University of Texas at El Paso, El Paso, Texas 79958, USA
| | - Shusil Bhusal
- Department of Physics, The University of Texas at El Paso, El Paso, Texas 79958, USA
| | - Luis Basurto
- Department of Physics, The University of Texas at El Paso, El Paso, Texas 79958, USA
| | - Tunna Baruah
- Department of Physics, The University of Texas at El Paso, El Paso, Texas 79958, USA
- Computational Science Program, The University of Texas at El Paso, El Paso, Texas 79958, USA
| | - Koblar Jackson
- Physics Department and Science of Advanced Materials Ph.D. Program, Central Michigan University, Mt. Pleasant, Michigan 48859, USA
| |
Collapse
|
6
|
Wirz LN, Tonner R, Hermann A, Sure R, Schwerdtfeger P. From small fullerenes to the graphene limit: A harmonic force-field method for fullerenes and a comparison to density functional calculations for Goldberg-Coxeter fullerenes up to C980. J Comput Chem 2015; 37:10-7. [DOI: 10.1002/jcc.23894] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2015] [Revised: 02/17/2015] [Accepted: 02/21/2015] [Indexed: 01/28/2023]
Affiliation(s)
- Lukas N. Wirz
- Centre for Theoretical Chemistry and Physics; The New Zealand Institute for Advanced Study, Massey University Auckland; Private Bag 102904 0745 Auckland New Zealand
| | - Ralf Tonner
- Fachbereich Chemie; Philipps-Universität Marburg; Hans-Meerwein-Str. D-35032 Marburg Germany
| | - Andreas Hermann
- Centre for Science at Extreme Conditions and SUPA, School of Physics and Astronomy; The University of Edinburgh; Edinburgh EH9 3FD United Kingdom
| | - Rebecca Sure
- Mulliken Center for Theoretical Chemistry; University of Bonn, Beringstr. 4; 53115 Bonn Germany
| | - Peter Schwerdtfeger
- Centre for Theoretical Chemistry and Physics; The New Zealand Institute for Advanced Study; Massey University Auckland, Private Bag 102904 0745 Auckland New Zealand
- Fachbereich Chemie, Philipps-Universität Marburg; Hans-Meerwein-Str.; D-35032 Marburg Germany
| |
Collapse
|
7
|
Poddar NN, Amar JG. Adsorption and diffusion of colloidal Au nanoparticles at a liquid-vapor interface. J Chem Phys 2014; 140:244702. [PMID: 24985663 DOI: 10.1063/1.4884022] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Motivated by recent drop-drying experiments of Au nanoparticle (NP) island self-assembly, we investigate the structure, diffusion, and binding of dodecanethiol-coated Au NPs adsorbed at the toluene-vapor interface using molecular dynamics (MD) simulations as well as analytical calculations. For a 6 nm core diameter NP our results indicate the existence of significant intermixing between the ligands and the solvent. As a result, the NP lies primarily below the interface with only a portion of the ligands sticking out, while the toluene-vapor interface is significantly higher in the region above the NP core than away from the NP. These results are consistent with a competition between the negative free energy of mixing of toluene and the dodecanethiol ligands, which tends to keep the NP below the interface, and the effects of surface tension which keeps the NP near the interface. Consistent with this result, we find that the coefficient for nanoparticle diffusion along the interface is close to the Stokes-Einstein prediction for three-dimensional bulk diffusion. An analysis of the ligand arrangement surrounding the NP also indicates that there is relatively little asymmetry in the ligand-coating. We then consider the effects of van der Waals interactions on the adsorption energy. In particular, we derive an analytical expression for the van der Waals interaction energy between a coated nanoparticle and the surrounding solvent along with a closed-form expression for the van der Waals corrections to the binding energy at the interface due to the long-range core-solvent interaction. Using these results along with the results of our MD simulations, we then estimate the van der Waals corrections to the adsorption energy for dodecanethiol-coated Au nanoparticles at the toluene-vapor interface as well as for decanethiol-coated nanoparticles at the water-vapor interface. In both cases, we find that the long-range core-solvent interaction may significantly reduce the binding energy. Based on these results, we conclude that in many cases, the core-solvent van der Waals interaction is likely to have a significant effect on the binding energy and interface position of Au NPs. Our results also indicate that the competition between the van der Waals interaction and the short-range attraction to the interface leads to the existence of well-defined activation barriers for nanoparticle adsorption from the solvent as well as for interfacial desorption.
Collapse
Affiliation(s)
- Nitun N Poddar
- Department of Electrical Engineering and Computer Science, University of Toledo, Toledo, Ohio 43606, USA
| | - Jacques G Amar
- Department of Physics and Astronomy, University of Toledo, Toledo, Ohio 43606, USA
| |
Collapse
|
8
|
Janner A. Alternative approaches to onion-like icosahedral fullerenes. ACTA CRYSTALLOGRAPHICA A-FOUNDATION AND ADVANCES 2014; 70:168-80. [DOI: 10.1107/s2053273313034219] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/12/2013] [Accepted: 12/19/2013] [Indexed: 11/11/2022]
Abstract
The fullerenes of the C60series (C60, C240, C540, C960, C1500, C2160etc.) form onion-like shells with icosahedralIhsymmetry. Up to C2160, their geometry has been optimized by Dunlap & Zope from computations according to the analytic density-functional theory and shown by Wardman to obey structural constraints derived from an affine-extendedIhgroup. In this paper, these approaches are compared with models based on crystallographic scaling transformations. To start with, it is shown that the 56 symmetry-inequivalent computed carbon positions, approximated by the corresponding ones in the models, are mutually related by crystallographic scalings. This result is consistent with Wardman's remark that the affine-extension approach simultaneously models different shells of a carbon onion. From the regularities observed in the fullerene models derived from scaling, an icosahedral infinite C60onion molecule is defined, with shells consisting of all successive fullerenes of the C60series. The structural relations between the C60onion and graphite lead to a one-parameter model with the same Euclidean symmetryP63mcas graphite and having ac/a= τ2ratio, where τ = 1.618… is the golden number. This ratio approximates (up to a 4% discrepancy) the value observed in graphite. A number of tables and figures illustrate successive steps of the present investigation.
Collapse
|
9
|
García G, Atilhan M, Aparicio S. A theoretical study on ionic liquid endohedral C540 fullerene. RSC Adv 2014. [DOI: 10.1039/c4ra07239a] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The effect of the confinement of ionic liquid (choline benzoate) cluster inside C540 fullerene has been studied through both molecular dynamic and density functional theory simulations.
Collapse
Affiliation(s)
- Gregorio García
- Department of Chemistry
- University of Burgos
- 09001 Burgos, Spain
| | - Mert Atilhan
- Department of Chemical Engineering
- Qatar University
- Doha, Qatar
| | | |
Collapse
|
10
|
Noël Y, De La Pierre M, Zicovich-Wilson CM, Orlando R, Dovesi R. Structural, electronic and energetic properties of giant icosahedral fullerenes up to C6000: insights from an ab initio hybrid DFT study. Phys Chem Chem Phys 2014; 16:13390-401. [DOI: 10.1039/c4cp01442a] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
An accurate and detailed electronic structure study of giant carbon fullerenes, benefitting from improved symmetry exploitation in the CRYSTAL14 code.
Collapse
Affiliation(s)
- Yves Noël
- Institut des Sciences de la Terre de Paris (UMR 7193 UPMC-CNRS)
- UPMC
- Sorbonne Universités
- Paris, France
| | - Marco De La Pierre
- Dipartimento di Chimica
- Università di Torino and NIS
- Nanostructured Interfaces and Surfaces
- Centre of Excellence
- 10125 Torino, Italy
| | | | - Roberto Orlando
- Dipartimento di Chimica
- Università di Torino and NIS
- Nanostructured Interfaces and Surfaces
- Centre of Excellence
- 10125 Torino, Italy
| | - Roberto Dovesi
- Dipartimento di Chimica
- Università di Torino and NIS
- Nanostructured Interfaces and Surfaces
- Centre of Excellence
- 10125 Torino, Italy
| |
Collapse
|
11
|
Vosel SV, Onischuk AA, Purtov PA, Nasibulin AG. Fluctuation theory of single-walled carbon nanotube formation. J Chem Phys 2013; 139:204705. [DOI: 10.1063/1.4830395] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
|
12
|
Xu J, Li Y, Xiang Y, Chen X. Energy absorption ability of buckyball C720 at low impact speed: a numerical study based on molecular dynamics. NANOSCALE RESEARCH LETTERS 2013; 8:54. [PMID: 23360618 PMCID: PMC3576260 DOI: 10.1186/1556-276x-8-54] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/07/2012] [Accepted: 01/16/2013] [Indexed: 06/01/2023]
Abstract
The dynamic impact response of giant buckyball C720 is investigated by using molecular dynamics simulations. The non-recoverable deformation of C720 makes it an ideal candidate for high-performance energy absorption. Firstly, mechanical behaviors under dynamic impact and low-speed crushing are simulated and modeled, which clarifies the buckling-related energy absorption mechanism. One-dimensional C720 arrays (both vertical and horizontal alignments) are studied at various impact speeds, which show that the energy absorption ability is dominated by the impact energy per buckyball and less sensitive to the number and arrangement direction of buckyballs. Three-dimensional stacking of buckyballs in simple cubic, body-centered cubic, hexagonal, and face-centered cubic forms are investigated. Stacking form with higher occupation density yields higher energy absorption. The present study may shed lights on employing C720 assembly as an advanced energy absorption system against low-speed impacts.
Collapse
Affiliation(s)
- Jun Xu
- Columbia Nanomechanics Research Center, Department of Earth and Environmental Engineering, Columbia University, New York, NY 10027, USA
| | - Yibing Li
- State Key Laboratory of Automotive Safety and Energy, Department of Automotive Engineering, Tsinghua University, Beijing, 100084, People’s Republic of China
| | - Yong Xiang
- State Key Lab of Electronic Thin Films and Integrated Devices, School of Energy Science and Engineering, University of Electronic Science and Technology of China, Chengdu, Sichuan 611731, People’s Republic of China
| | - Xi Chen
- Columbia Nanomechanics Research Center, Department of Earth and Environmental Engineering, Columbia University, New York, NY 10027, USA
- Department of Civil and Environmental Engineering, Hanyang University, Seoul, 133-791, South Korea
- International Center for Applied Mechanics, SV Lab, Xi’an Jiaotong University, Xi’an, 710049, People’s Republic of China
| |
Collapse
|
13
|
Rodríguez-Fortea A, Irle S, Poblet JM. Fullerenes: formation, stability, and reactivity. WILEY INTERDISCIPLINARY REVIEWS-COMPUTATIONAL MOLECULAR SCIENCE 2011. [DOI: 10.1002/wcms.21] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
|
14
|
Remarkable diversity of carbon–carbon bonds: structures and properties of fullerenes, carbon nanotubes, and graphene. Struct Chem 2010. [DOI: 10.1007/s11224-010-9670-2] [Citation(s) in RCA: 84] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
|
15
|
Lane JMD, Grest GS. Spontaneous asymmetry of coated spherical nanoparticles in solution and at liquid-vapor interfaces. PHYSICAL REVIEW LETTERS 2010; 104:235501. [PMID: 20867251 DOI: 10.1103/physrevlett.104.235501] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/23/2010] [Indexed: 05/21/2023]
Abstract
Spherical nanoparticles (NPs), uniformly coated with a simple polymer used to passivate NPs in solution, are shown to produce highly asymmetric coating arrangements. We show that a class of spherical particles is not symmetrically coated even when extremely uniform grafting arrangements and full coverages are employed. We demonstrate, using explicit-atom molecular dynamics simulations of model NPs, that geometric properties dictate when a coating's spherical symmetry will be unstable and show that the chain end group and the solvent play a secondary role in determining the properties of surface patterns. At the water-vapor interface the coatings are significantly distorted and oriented by the surface. These asymmetric and oriented coatings are expected to have a dramatic effect on the interactions between NPs and will likely influence the structures of aggregated NPs which self-assemble in the bulk and at surfaces.
Collapse
Affiliation(s)
- J Matthew D Lane
- Sandia National Laboratories, Albuquerque, New Mexico 87185, USA.
| | | |
Collapse
|
16
|
|
17
|
Calaminici P, Geudtner G, Köster AM. First-Principle Calculations of Large Fullerenes. J Chem Theory Comput 2008; 5:29-32. [DOI: 10.1021/ct800347u] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Patrizia Calaminici
- Departamento de Química, CINVESTAV, Avenida Instituto Politecnico Nacional 2508, A.P. 14-740, Mexico D.F. 07000, Mexico
| | - Gerald Geudtner
- Departamento de Química, CINVESTAV, Avenida Instituto Politecnico Nacional 2508, A.P. 14-740, Mexico D.F. 07000, Mexico
| | - Andreas M. Köster
- Departamento de Química, CINVESTAV, Avenida Instituto Politecnico Nacional 2508, A.P. 14-740, Mexico D.F. 07000, Mexico
| |
Collapse
|
18
|
|
19
|
Jing Q, Tian FY, Wang YX. No quenching of magnetic moment for the GenCo (n=1-13) clusters: first-principles calculations. J Chem Phys 2008; 128:124319. [PMID: 18376931 DOI: 10.1063/1.2898880] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
The authors predict that for the Ge(n)Co (n=1-13) clusters the magnetic moment does not quench, which is dark contrast to the previous results with transition-metal-doped Si(n) clusters. It may be due to the unpaired electrons of the Co atom in the clusters. For the ground state structures of the Ge(n)Co (n>or=9) clusters, the Co atom completely falls into the center of the Ge outer frame, forming metal-encapsulated Ge(n) cages. The doping of the Co atom enhances the stability of the host Ge(n) clusters. The Ge(10)Co cluster with the bicapped tetragonal antiprism structure is more stable than others, which agrees very well with the results of the experiment of the Co/Ge binary clusters by the laser vaporization.
Collapse
Affiliation(s)
- Qun Jing
- Institute of Computational Materials Science, School of Physics and Electronics, Henan University, Kaifeng 475004, People's Republic of China
| | | | | |
Collapse
|
20
|
Dunlap BI, Karna SP, Zope RR. Dipole moments from atomic-number-dependent potentials in analytic density-functional theory. J Chem Phys 2006; 125:214104. [PMID: 17166012 DOI: 10.1063/1.2403854] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Molecular dipole moments of analytic density-functional theory are investigated. The effect of element-dependent exchange potentials on these moments are examined by comparison with conventional quantum-chemical methods and experiment for the subset of the extended G2 set of molecules that have nonzero dipole moment. Fitting the Kohn-Sham [Phys. Rev. 140, A1133 (1965)] potential itself makes a mean absolute error of less than 0.1 D. Variation of alpha (Slater's [Phys. Rev. 81, 385 (1951)] exchange parameter) values has far less effect on dipole moments than on energies. It is argued that in variable alpha methods one should choose the smaller of the two rather than the geometric mean of the two alpha values for the heteroatomic part of the linear-combination-atomic-orbital density. Calculations on the dipole moment of NH(2)(CH)(24)NO(2) are consistent with earlier calculations and show that varying the differences between alpha values for atoms with different atomic numbers has only short-ranged electrostatic effects.
Collapse
Affiliation(s)
- Brett I Dunlap
- Code 6189, Theoretical Chemistry Section, U.S. Naval Research Laboratory, Washington, DC 20375-5342, USA
| | | | | |
Collapse
|