BH-DFTB/DFT calculations for iron clusters
- Mechanical Engineering Department, Mevlana (Rumi) University, Konya 42003 (Turkey)
We present a study on the structural, electronic, and magnetic properties of Fe{sub n}(n = 2 − 20) clusters by performing density functional tight binding (DFTB) calculations within a basin hopping (BH) global optimization search followed by density functional theory (DFT) investigations. The structures, total energies and total spin magnetic moments are calculated and compared with previously reported theoretical and experimental results. Two basis sets SDD with ECP and 6-31G** are employed in the DFT calculations together with BLYP GGA exchange-correlation functional. The results indicate that the offered BH-DFTB/DFT strategy collects all the global minima of which different minima have been reported in the previous studies by different groups. Small Fe clusters have three kinds of packing; icosahedral (Fe{sub 9−13}), centered hexagonal antiprism (Fe{sub 14−17}, Fe{sub 20}), and truncated decahedral (Fe{sub 17(2)}, Fe{sub 18−19}). It is obtained in a qualitative agreement with the time of flight mass spectra that the magic numbers for the small Fe clusters are 7, 13, 15, and 19 and with the collision induced dissociation experiments that the sizes 6, 7, 13, 15, and 19 are thermodynamically more stable than their neighboring sizes. The spin magnetic moment per atom of Fe{sub n}(n = 2 − 20) clusters is between 2.4 and 3.6 μ{sub B} for the most of the sizes. The antiferromagnetic coupling between the central and the surface atoms of the Fe{sub 13} icosahedron, which have already been reported by experimental and theoretical studies, is verified by our calculations as well. The quantitative disagreements between the calculations and measurements of the magnetic moments of the individual sizes are still to be resolved.
- OSTI ID:
- 22611702
- Journal Information:
- AIP Advances, Journal Name: AIP Advances Journal Issue: 5 Vol. 6; ISSN AAIDBI; ISSN 2158-3226
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ANTIFERROMAGNETISM
ATOMIC CLUSTERS
ATOMS
COMPARATIVE EVALUATIONS
COMPUTERIZED SIMULATION
CORRELATIONS
CRYSTAL STRUCTURE
DENSITY FUNCTIONAL METHOD
DISSOCIATION
ELECTRICAL PROPERTIES
IRON
MAGIC NUCLEI
MAGNETIC MOMENTS
MAGNETIC PROPERTIES
MASS
MASS SPECTRA
OPTIMIZATION
SPIN
SURFACES
TIME-OF-FLIGHT METHOD