Effect of charge distribution on RDX adsorption in IRMOF-10

Journal Article · Thu Dec 31 23:00:00 EST 2009 · Langmuir

DOI:https://doi.org/10.1021/la9039013· OSTI ID:982741

Xiong, Ruichang ^[1]; Keffer, David J. ^[1]; Fuentes-Cabrera, Miguel A ^[2]; Nicholson, Don M ^[2]; Michalkova, Andrea ^[3]; Petrova, Tetyana ^[3]; Leszczynski, Jerzy ^[4]; Odbadrakh, Khorgolkhuu ^[2]; Doss, Bryant ^[5]; Lewis, James ^[5]

---

1. University of Tennessee, Knoxville (UTK)
2. ORNL
3. Jackson State University
4. Computational Center for Molecular Structure and Interactions, Jackson, MS
5. West Virginia University, Morgantown

Quantum mechanical (QM) calculations, classical grand canonical Monte Carlo (GCMC) simulations, and classical molecular dynamics (MD) simulations are performed to test the effect of charge distribution on hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) adsorption and diffusion in IRMOF-10. Several different methods for mapping QM electron distributions onto atomic point charges are explored, including the electrostatic potential (ESP) method, Mulliken population analysis, L{sub 0}wdin population analysis, and natural bond orbital analysis. Classical GCMC and MD simulations of RDX in IRMOF-10 are performed using 15 combinations of charge sources of RDX and IRMOF-10. As the charge distributions vary, interaction potential energies, the adsorption loading, and the self-diffusivities are significantly different. None of the 15 combinations are able to quantitatively capture the dependence of the energy of adsorption on local configuration of RDX as observed in the QM calculations. We observe changes in the charge distributions of RDX and IRMOF-10 with the introduction of an RDX molecule into the cage. We also observe a large dispersion contribution to the interaction energy from QM calculations that is not reproduced in the classical simulations, indicating that the source of discrepancy may not lie exclusively with the assignment of charges.

• Research Organization: Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States). Oak Ridge Leadership Computing Facility (OLCF); Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States). Center for Nanophase Materials Sciences (CNMS)
• Sponsoring Organization: USDOE Office of Science (SC)
• DOE Contract Number: AC05-00OR22725
• OSTI ID: 982741
• Journal Information: Langmuir, Journal Name: Langmuir Journal Issue: 8 Vol. 26; ISSN 0743-7463; ISSN 1520-5827
• Country of Publication: United States
• Language: English