Appropriate description of intermolecular interactions in the methane hydrates: An assessment of DFT methods

Abstract

Accurate description of hydrogen-bonding energies between water molecules and van der Waals interactions between guest molecules and host water cages is crucial for study of methane hydrates (MHs). Using high-level ab initio MP2 and CCSD(T) results as the reference, we carefully assessed the performance of a variety of exchange-correlation functionals and various basis sets in describing the noncovalent interactions in MH. The functionals under investigation include the conventional GGA, meta-GGA, and hybrid functionals (PBE, PW91, TPSS, TPSSh, B3LYP, and X3LYP), long-range corrected functionals (ωB97X, ωB97, LC-ωPBE, CAM-B3LYP, and LC-TPSS), the newly developed Minnesota class functionals (M06-L, M06-HF, M06, and M06-2X), and the dispersion-corrected density functional theory (DFT) (DFT-D) methods (B97-D, ωB97X-D, PBE-TS, PBE-Grimme, and PW91-OBS). We found that the conventional functionals are not suitable for MH, notably, the widely used B3LYP functional even predicts repulsive interaction between CH(4) and (H(2)O)(6) cluster. M06-2X is the best among the M06-Class functionals. The ωB97X-D outperforms the other DFT-D methods and is recommended for accurate first-principles calculations of MH. B97-D is also acceptable as a compromise of computational cost and precision. Considering both accuracy and efficiency, B97-D, ωB97X-D, and M06-2X functional with 6-311++G(2d,2p) basis set without basis set superposition error (BSSE) correction are recommended. Though a fairly large basis set (e.g., aug-cc-pVTZ) and BSSE correction are necessary for a reliable MP2 calculation, DFT methods are less sensitive to the basis set and BSSE correction if the basis set is sufficient (e.g., 6-311++G(2d,2p)). These assessments provide useful guidance for choosing appropriate methodology of first-principles simulation of MH and related systems. © 2012 Wiley Periodicals, Inc.

Raman and IR Spectra of Ice Ih and Ice XI with an Assessment of DFT Methods

“…H-bond and van der Waals interactions) in the DFT framework being a challenge, different exchange-correlation functionals are assessed as in previous studies. 48 59,65 ). Except for BLYP and HCTH, the methods are employed using plan-wave basis sets with norm-conserving pseudopotentials in the CASTEP 66 program in Materials Studio 6.1.…”

Fingerprints in IR OH vibrational spectra of H2O clusters from different H-bond conformations by means of quantum-chemical computations

“…[2,3,6,7,17,27,28] The widely used dodecahedral water cluster model (H 2 O) 20 (Figure 1(a)), which notably only contains 3-coordinated (3c) water molecules, is a cavity motif in clathrate hydrates. [8] The water cluster of medium size, i.e. (H 2 O) 54 (Figure 1(b)), was likewise constructed from a clathrate structure, but six water molecules were added to the interior of the cage so that both 3c and 4-coordinated (4c) water molecules are represented.…”

“…[1] Clusters of water molecules are subject to many scientific studies due to their importance in atmospheric chemistry, cloud and ice formation, and biochemical processes. [1][2][3][4][5][6][7][8] The exploration of structural and binding properties of water clusters may provide a route to understand bulk water in its liquid or solid phase. [1,9] Thus many studies have been presented on the structure of water clusters from small to large sizes both experimentally and theoretically.…”

C–C Stretching Raman Spectra and Stabilities of Hydrocarbon Molecules in Natural Gas Hydrates: A Quantum Chemical Study

“…[28][29][30][31] The nucleation, growth, and dissociation process has been investigated by MD simulations in the last few years. [32][33][34][35][36][37][38] In the quantum-chemical investigations most focus has been on the interaction between host and guest molecules, [39][40] stability and diffusion of guest molecules in water cavities of clathrate hydrates, [41][42][43][44] and phase transitions. [45][46] Liu et al evaluated the performance of twenty density functional theory (DFT) methods for the description of the intermolecular interaction in methane hydrates.…”

“…[45][46] Liu et al evaluated the performance of twenty density functional theory (DFT) methods for the description of the intermolecular interaction in methane hydrates. 39 Roman-Perez et al calculated the adsorption energies of different guest molecules captured in the water cavities from clathrate hydrates based on DFT. 43 Li et al studied the barriers of H2 and CH4 diffusion through the water framework in hydrates using dispersion-corrected DFT.…”