@article {541, title = {Selective capture of CO$_{2}$ over N$_{2}$ and CH$_{4}$: B clusters and their size effects}, journal = {Mater. Today Commun.}, volume = {22}, year = {2020}, pages = {100712}, abstract = {Using density-functional theory (DFT), we investigate the selectivity of adsorption of CO$_{2}$ over N$_{2}$ and CH$_{4}$ on planar-type B clusters, based on our previous finding of strong chemisorption of CO$_{2}$ on the B$_{1}$$_{0}$$_{-}$$_{1}$$_{3}$ planar and quasiplanar clusters. We consider the prototype B$_{8}$ and B$_{1}$$_{2}$ planar-type clusters and perform a comparative study of the adsorption of the three molecules on these clusters. We find that, at room temperature, CO$_{2}$ can be separated from N$_{2}$ by selective binding to the B$_{1}$$_{2}$ cluster and not to the B$_{8}$ cluster. Selective adsorption of CO$_{2}$ over CH$_{4}$ at room temperature is possible for both clusters. Based on our DFT-adsorption data (including also a semi-infinite Boron sheet) and the available literature-adsorption value for N$_{2}$ on the planar-type B$_{3}$$_{6}$ cluster, we discuss the selectivity trend of CO$_{2}$ adsorption over N$_{2}$ and CH$_{4}$ with planar-cluster size, showing that it extends over sizes including B$_{1}$$_{0}$$_{-}$$_{1}$$_{3}$ clusters and significantly larger.}, doi = {10.1016/j.mtcomm.2019.100712}, url = {https://www.sciencedirect.com/science/article/abs/pii/S2352492819305719}, author = {Alexandra B. Santos-Putungan and Nata{\v s}a Stoji{\'c} and Nadia Binggeli and Francis N. C. Paraan} } @article {498, title = {Strong chemisorption of CO$_{2}$ on B$_{1}$$_{0}${\textendash}B$_{1}$$_{3}$ planar-type clusters}, journal = {J. Phys. Condens. Matter}, volume = {31}, year = {2019}, pages = {145504}, abstract = {
An ab initio density functional study was performed investigating the adsorption of CO$_{2}$ on neutral boron Bₙ (n = 10{\textendash}13) clusters that are characterized by planar and quasiplanar ground-state atomic structures. For all four clusters, we found large chemisorption binding energies, reaching 1.6 eV between CO$_{2}$ and B$_{1}$$_{2}$, with the adsorbed molecule oriented in the plane of the cluster and adsorbed along the cluster edge. A configuration with chemisorbed dissociated CO$_{2}$ molecule also exists for B$_{1}$$_{1}$ and B$_{1}$$_{3}$ clusters. The strong adsorption is due to the bending of the CO$_{2}$ molecule, which provides energetically accessible fully in-plane frontier molecular orbitals matching the edge states of the clusters. At the same time, the intrinsic dipole moment of a bent CO$_{2}$ molecule facilitates the transfer of excess electronic charge from the cluster edges to the molecule.
}, doi = {10.1088/1361-648x/aafebd}, author = {Alexandra B. Santos-Putungan and Nata{\v s}a Stoji{\'c} and Nadia Binggeli and Francis N. C. Paraan} } @conference {430, title = {Strong chemisorption of CO on neutral B13 cluster edge site}, year = {2017}, month = {8{\textendash}11 Aug 2017}, pages = {PS-03}, publisher = {9th Conference of Asian Consortium on Computational Materials Science}, address = {Kuala Lumpur, Malaysia}, abstract = {We investigate the interaction of carbon monoxide (CO) molecule with neutral boron 13 (B13) cluster using spin-polarized density functional theory (DFT). We found that the edge sites of B13 cluster is the most reactive part, with strong CO adsorption of around -1.67 eV. Molecular orbitals analysis of the cluster shows that~the HOMO nearest to the Fermi level contributes to the adsorption of CO molecule. Our results indicate that~B13 cluster~could have potential applications in the storage and sequestration of CO molecules.}, url = {https://umconference.um.edu.my/accms-9}, author = {Alexandra B. Santos-Putungan and Nata{\v s}a Stoji{\'c} and Nadia Binggeli and Francis N. C. Paraan} } @inproceedings {309, title = {Investigation of neutral B13 clusters: A density functional theory study}, booktitle = {Proceedings of the 34th Samahang Pisika ng Pilipinas Physics Congress}, year = {2016}, month = {18{\textendash}21 Aug 2016}, pages = {SPP-2016-PA-18}, address = {University of the Philippines Visayas, Iloilo City}, abstract = {We investigate the electronic structure of neutral boron_13 (B13) clusters using spin-polarized density functional theory (DFT). The stable B13 cluster is observed to have a two-dimensional planar structure. Energy levels diagram shows that it has a highest occupied molecular orbital{\textendash}lowest unoccupied molecular orbital (HOMO-LUMO) gap of 0.36 eV. Analysis of the electronic charge density of the B13 cluster reveals that most of the electrons are shared between B atoms and are located at the edges, where the HOMO and LUMO are also localized. Our results indicate that the most reactive part of the cluster is along its edges.}, author = {Alexandra B. Santos-Putungan and Nata{\v s}a Stoji{\'c} and Nadia Binggeli and Francis N. C. Paraan} } @conference {santos-putungan-qpcmp-2015, title = {Computational materials science via density functional theory: General introduction and success stories}, year = {2015}, month = {22{\textendash}23 Apr 2015}, publisher = {Workshop on Theories in Quantum Phenomena and Condensed Matter Physics}, address = {University of the Philippines Los Ba{\~n}os, Laguna}, url = {https://imsp.uplb.edu.ph/index.php/component/content/article/17-imsp-news/research/370-workshop-on-theories-in-quantum-phenomena-and-condensed-matter-physics}, author = {Alexandra B. Santos-Putungan} } @inproceedings {santosputungan-spp-2015, title = {Enhanced ferromagnetism in Zn0.5 (Co)0.5 O alloy: DFT calculations}, booktitle = {Proceedings of the 33rd Samahang Pisika ng Pilipinas Physics Congress}, year = {2015}, month = {3{\textendash}6 Jun 2015}, pages = {SPP-2015-PA-14}, address = {University of Northern Philippines, Vigan City}, abstract = {