Computational study of molecular hydrogen in zeolite Na-A. I. Potential energy surfaces and thermodynamic separation factors for <i>ortho</i> and <i>para</i> hydrogen

Anderson, Cherry-Rose; Coker, David F.; Eckert, Juergen; Bug, A. L. R.

doi:10.1063/1.480104

Cited by 37 publications

(34 citation statements)

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“…There have been a number of experimental studies of H 2 and its isotopes within or on the surface of solids such as the rare gases, 7 alkali-metal halides, 8,9 silica, 10 zeolites, [11][12][13][14][15] and carbon nanotubes, 16 along with GaAs 17 and silicon. 18 -20 In some of the former cases, purely vibrational transitions have been detected in IR.…”

Section: H 2 Within or On The Surface Of Solidsmentioning

confidence: 99%

Dynamics of interstitialH2in crystalline silicon

2002

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The dynamics of interstitial H 2 and its isotopes in crystalline silicon have been studied by using a potentialenergy function for the molecule that consists of the superposition of potentials for two separated hydrogen atoms as generated from the quantum-mechanical calculations of Porter, Towler, and Needs. The rotational properties were calculated using the approach of Martin and Fowler and the vibrational properties of the molecules as a whole were obtained. The results of these calculations indicate nearly free rotational motion, consistent with shallow rotational potentials. Confinement of the molecules leads to center-of-mass vibrations of a few hundred wave numbers and dynamical ''off-centeredness'' that breaks tetrahedral symmetry and allows purely vibrational transitions to occur. This approach has also been used to investigate tetrahedral interstitial H 2 adjacent to a bond-centered oxygen atom. The results of these calculations provide a framework for understanding the rovibrational properties of H 2 and O-H 2 and their isotopes, including experiments involving uniaxial stress.

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Section: H 2 Within or On The Surface Of Solidsmentioning

confidence: 99%

Dynamics of interstitialH2in crystalline silicon

2002

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“…49 The feasibility of hydrogen storage in zeolites, MOFs and metal decorated carbon nanostructures, has been addressed computationally through recent ab initio and density functional theory (DFT) studies. [53][54][55][56][57][58] Rotationally resolved spectra of gas-phase M + -H 2 complexes provide a particularly stringent set of data against which calculated properties can be benchmarked and should help guide the choice of a computational method that achieves a balance between computational expediency and chemical accuracy. A prudent approach involves choosing a computational strategy that is benchmarked through predictions of the structural and energetic properties of the simple, isolated M + -H 2 complexes, which is then deployed to treat larger, more complicated HSM systems.…”

Section: Practical Motivationsmentioning

confidence: 99%

Attaching molecular hydrogen to metal cations: perspectives from gas-phase infrared spectroscopy

Dryza

Poad

Bieske

2012

Phys. Chem. Chem. Phys.

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In this perspective article we describe recent infrared spectroscopic investigations of mass-selected M(+)-H(2) and M(+)-D(2) complexes in the gas-phase, with targets that include Li(+)-H(2), B(+)-H(2), Na(+)-H(2), Mg(+)-H(2), Al(+)-H(2), Cr(+)-D(2), Mn(+)-H(2), Zn(+)-D(2) and Ag(+)-H(2). Interactions between molecular hydrogen and metal cations play a key role in several contexts, including in the storage of molecular hydrogen in zeolites, metal-organic frameworks, and doped carbon nanostructures. Arguably, the clearest view of the interaction between dihydrogen and a metal cation can be obtained by probing M(+)-H(2) complexes in the gas phase, free from the complicating influences of solvents or substrates. Infrared spectra of the complexes in the H-H and D-D stretch regions are obtained by monitoring M(+) photofragments as the excitation wavelength is scanned. The spectra, which feature full rotational resolution, confirm that the M(+)-H(2) complexes share a common T-shaped equilibrium structure, consisting essentially of a perturbed H(2) molecule attached to the metal cation, but that the structural and vibrational parameters vary over a considerable range, depending on the size and electronic structure of the metal cation. Correlations are established between intermolecular bond lengths, dissociation energies, and frequency shifts of the H-H stretch vibrational mode. Ultimately, the M(+)-H(2) and M(+)-D(2) infrared spectra provide a comprehensive set of benchmarks for modelling and understanding the M(+)···H(2) interaction.

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“…In part I of this series, 1 we introduced a Monte Carlo ͑MC͒ simulation of adsorbed H 2 in the zeolite Na-A. Realistic guest-host interaction potentials and a quantum mechanical treatment of the rotations of the H 2 molecule were used within the context of a MC sampling procedure.…”

Section: Introductionmentioning

confidence: 99%

Computational study of molecular hydrogen in zeolite Na–A. II. Density of rotational states and inelastic neutron scattering spectra

MacKinnon

Eckert

Coker

et al. 2001

The Journal of Chemical Physics

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Articles you may be interested inProbing the hydrogen equilibrium and kinetics in zeolite imidazolate frameworks via molecular dynamics and quasi-elastic neutron scattering experiments J. Chem. Phys. 138, 034706 (2013); 10.1063/1.4774375An inelastic incoherent neutron scattering study of water in small-pored zeolites and other water-bearing minerals Computational study of molecular hydrogen in zeolite Na-A. I. Potential energy surfaces and thermodynamic separation factors for ortho and para hydrogen Part I of this series ͓J. Chem. Phys. 111, 7599 ͑1999͔͒ describes a simulation of H 2 adsorbed within zeolite Na-A in which a block Lanczos procedure is used to generate the first several ͑9͒ rotational eigenstates of H 2 , modeled as a rigid rotor, and equilibrated at a given temperature via Monte Carlo sampling. Here, we show that rotational states are strongly perturbed by the electrostatic fields in the solid. Wave functions and densities of rotational energy states are presented. Simulated neutron spectra are compared with inelastic neutron scattering data. Comparisons are made with IR spectra in which rotational levels may appear due to rovibrational coupling.

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Computational study of molecular hydrogen in zeolite Na-A. I. Potential energy surfaces and thermodynamic separation factors for ortho and para hydrogen

Cited by 37 publications

References 83 publications

Dynamics of interstitialH2in crystalline silicon

Dynamics of interstitialH2in crystalline silicon

Attaching molecular hydrogen to metal cations: perspectives from gas-phase infrared spectroscopy

Computational study of molecular hydrogen in zeolite Na–A. II. Density of rotational states and inelastic neutron scattering spectra

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