Abstract
We simulate H2 adsorbed within zeolite Na-A. We use a block Lanczos procedure to generate the first several (9) rotational eigenstates of the molecule, which is modeled as a rigid, quantum rotor with an anisotropic polarizability and quadrupole moment. The rotor interacts with Na cations and O anions; interaction parameters are chosen semiempirically and the truncation of electrostatic fields is handled with a switching function. A Monte Carlo proceedure is used to sample a set of states based on the canonical distribution. Potential energy surfaces, favorable adsorbtion sites, and distributions of barriers to rotation are analyzed. Separation factors for ortho-parahydrogen are calculated; at low temperatures, these are controlled by the ease of rotational tunneling through barriers.
Original language | English |
---|---|
Pages (from-to) | 7599-7613 |
Number of pages | 15 |
Journal | Journal of Chemical Physics |
Volume | 111 |
Issue number | 16 |
DOIs | |
State | Published - Oct 22 1999 |