skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Influence of molecular shape on self-diffusion under severe confinement: A molecular dynamics study

Abstract

In this study, we have investigated the effect of molecular shape and charge asymmetry on the translation dynamics of confined hydrocarbon molecules having different shapes but similar kinetic diameters, inside ZSM-5 pores using molecular dynamics simulations. The mean square displacement of propane, acetonitrile, acetaldehyde, and acetone in ZSM-5 exhibit two different regimes – ballistic and diffusive/sub-diffusive. All the molecules except propane exhibit sub-diffusive motion at time scales greater than 1 ps. The intermediate scattering functions reveal that there is a considerable rotational-translational coupling in the motion of all the molecules, due to the strong geometrical restriction imposed by ZSM-5. Overall the difference in shape and asymmetry in charge imposes severe restriction inside the ZSM-5 channels for all the molecules to different extents. Additionally, the behavior of molecules confined in ZSM-5 in the present study, quantified wherever possible, is compared to their behavior in bulk or in other porous media reported in literature.

Authors:
ORCiD logo [1]; ORCiD logo [2]; ORCiD logo [3];  [4];  [4]
  1. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Neutron Scattering Division
  2. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). UT/ORNL Center for Molecular Biophysics, Biosciences Division
  3. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Computational Science and Engineering Division
  4. The Ohio State Univ., Columbus, OH (United States). School of Earth Sciences
Publication Date:
Research Org.:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22). Chemical Sciences, Geosciences & Biosciences Division
OSTI Identifier:
1474635
DOE Contract Number:  
AC05-00OR22725; SC0006878
Resource Type:
Journal Article
Journal Name:
Chemical Physics
Additional Journal Information:
Journal Volume: 516; Journal Issue: C; Journal ID: ISSN 0301-0104
Publisher:
Elsevier
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY

Citation Formats

Dhiman, Indu, Shrestha, Utsab R., Bhowmik, Debsindhu, Cole, David, and Gautam, Siddharth. Influence of molecular shape on self-diffusion under severe confinement: A molecular dynamics study. United States: N. p., 2018. Web. doi:10.1016/j.chemphys.2018.08.033.
Dhiman, Indu, Shrestha, Utsab R., Bhowmik, Debsindhu, Cole, David, & Gautam, Siddharth. Influence of molecular shape on self-diffusion under severe confinement: A molecular dynamics study. United States. doi:10.1016/j.chemphys.2018.08.033.
Dhiman, Indu, Shrestha, Utsab R., Bhowmik, Debsindhu, Cole, David, and Gautam, Siddharth. Fri . "Influence of molecular shape on self-diffusion under severe confinement: A molecular dynamics study". United States. doi:10.1016/j.chemphys.2018.08.033.
@article{osti_1474635,
title = {Influence of molecular shape on self-diffusion under severe confinement: A molecular dynamics study},
author = {Dhiman, Indu and Shrestha, Utsab R. and Bhowmik, Debsindhu and Cole, David and Gautam, Siddharth},
abstractNote = {In this study, we have investigated the effect of molecular shape and charge asymmetry on the translation dynamics of confined hydrocarbon molecules having different shapes but similar kinetic diameters, inside ZSM-5 pores using molecular dynamics simulations. The mean square displacement of propane, acetonitrile, acetaldehyde, and acetone in ZSM-5 exhibit two different regimes – ballistic and diffusive/sub-diffusive. All the molecules except propane exhibit sub-diffusive motion at time scales greater than 1 ps. The intermediate scattering functions reveal that there is a considerable rotational-translational coupling in the motion of all the molecules, due to the strong geometrical restriction imposed by ZSM-5. Overall the difference in shape and asymmetry in charge imposes severe restriction inside the ZSM-5 channels for all the molecules to different extents. Additionally, the behavior of molecules confined in ZSM-5 in the present study, quantified wherever possible, is compared to their behavior in bulk or in other porous media reported in literature.},
doi = {10.1016/j.chemphys.2018.08.033},
journal = {Chemical Physics},
issn = {0301-0104},
number = C,
volume = 516,
place = {United States},
year = {2018},
month = {8}
}