Browsing by Author "Boustani, Ihsan"

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Citation Count: Taş, Murat..at all (2012). "Fragmentation and Coulomb explosion of multicharged small boron clusters", Physical Review B - Condensed Matter and Materials Physics, Vol. 85, No. 23.
Fragmentation and Coulomb explosion of multicharged small boron clusters
(2012) Taş, Murat; Akman, Nurten; Özdoǧan, Cem; Boustani, Ihsan; 40569
We extensively study the fragmentation and Coulomb explosion of multiply charged small boron clusters B n (n=2-13), where n is the cluster size. Our calculations are based on ab initio quantum-chemistry methods. Highly charged unstable clusters dissociate spontaneously into several neutral or charged fragments, and large amounts of energy are produced, depending on the charge of the parent cluster. We argue that this mechanism makes boron clusters a clean, safe, and cheap energetic material. © 2012 American Physical Society.
Citation Count: Akman, N...et al. (2011). Ionization energies, Coulomb explosion, fragmentation, geometric, and electronic structures of multicharged boron clusters B-n (n=2-13). Physical Review B , 84(7). http://dx.doi.org/10.1103/PhysRevB.84.075463
Ionization energies, Coulomb explosion, fragmentation, geometric, and electronic structures of multicharged boron clusters B-n (n=2-13)
(Amer Physical Soc, 2011) Akman, Nurten; Taş, Murat; Özdoğan, Cem; Boustani, Ihsan; 27617
Based on the ab initio quantum chemical methods, we have determined fragmentation channels, ionization energies, and the Coulomb explosion of multicharged boron clusters B-n (n = 2-13), where n is the cluster size. The electron-deficient boron clusters sustain more stability and hardly fragment when they are negatively charged. Stability of boron clusters decreases with increasing ionization. Only by the first ionization the odd-size clusters are more stable than the even-size clusters. Further ionizations cause the repulsive Coulomb force between the constituent atoms to get stronger, and lead first to metastable states, then to the Coulomb explosion of clusters. None of the cationic boron clusters studied remain stable after six times ionization. The critical charge for metastability is estimated as Q(m) <= n/2 for even-size clusters, and Q(m) <= 1/2 (n - 1) for odd-size clusters. In addition, the critical charge for the Coulomb explosion is found to be Q(c) = n/2 + 1 for even-size clusters, and Q(c) = 1/2(n + 1) for odd-size clusters. Relative stability of clusters with respect to their nearest neighbors is determined from the analysis of their second energy difference data. Several dissociation channels of B-n(+) and B-13(Q) isomers with the lowest fragmentation energies are presented. All of the vibrational frequencies are found positive indicating that no transition state is possible for the clusters studied. Reliability of our data is verified with a good agreement with experimental results
Citation Count: Özdoğan, C...et al. (2010). The unusually stable B-100 fullerene, structural transitions in boron nanostructures, and a comparative study of alpha- and gamma-boron and sheets. Journal of Physical Chemistry C, 114(10), 4362-4375. http://dx.doi.org/10.1021/jp911641u
The unusually stable B-100 fullerene, structural transitions in boron nanostructures, and a comparative study of alpha- and gamma-boron and sheets
(Amer Chemical Soc, 2010) Özdoğan, Cem; Mukhopadhyay, Saikat; Hayami, W.; Güvenç, Büşra; Pandey, Ravindra; Boustani, Ihsan
Solid alpha-B-12 rhombohedral and gamma-B-28 orthorhombic boron as well as boron nanostructures in the form of spheres, sheets, and multirings beside a ring consisting of icosahedral B-12 units were investigated using ab initio quantum chemical and density functional methods. The structure of the 131(x) fullerene exhibits unusual stability among all noninteracting free-standing Clusters, and is more stable than the 13120 cluster fragment of the gamma-B-28 solid, recently predicted and observed by Oganov et al. (Nature 2009, 457, 863). In addition, we compared the stability of the multirings and reported the structural transition from double-ring to triple-ring systems. This structural transition Occurs between B-52 and B-54 Clusters. We confirm that the noninteracting free-standing triangular buckled-sheet is more stable than the gamma-sheet, assembled in this work, and than the a-sheet, proposed by Tang and Ismail-Beigi (Phys. Rev. Lett. 2007, 99, 115501). In contrast, however, when these sheets are considered as infinite periodic systems, then the a-sheet remains the most stable one