Multicentred QM/QM methods for overlapping model systems

Hopkins, Brian W.; Tschumper, Gregory S.

doi:10.1080/00268970512331317291

Cited by 43 publications

(44 citation statements)

References 29 publications

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“…Many hybrid methods are available today that adopt a similar approach by applying two or more levels of theory to the many-body expansion, including extended ONIOM (XO), 223 the molecules in molecules method, 224,225 the hybrid many-body interaction method, 226, 227 the multilevel fragment-based approach, 228 the stratified approximation many-body approach, 229 and the Nbody:Many-body QM:QM technique developed by our group. [230][231][232][233][234][235][236] Ref 237 presents a general framework for and a very lucid overview of the various fragmentation procedures based on the many-body expansion.…”

Section: Strategies For Extending High-accuracy Methods To Larger Clumentioning

confidence: 99%

Wavefunction methods for the accurate characterization of water clusters

Howard

Tschumper

2013

WIREs Comput Mol Sci

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Although the first ab initio Hartree-Fock computations of the water dimer were reported more than four decades ago, the detailed characterization of water clusters with sophisticated electronic structure techniques remains an important and vibrant area of research. The field of computational quantum chemistry has made significant advances since those pioneering studies. Geometry optimizations of the water dimer can now be carried out at the CCSDTQ level, and CCSD(T) energies can be computed with the aug-cc-pVTZ basis for clusters as large as (H 2 O) 17 . Some of these high-level studies are starting to reveal that the electronic structure is harder to describe for some hydrogen bonds than others. For example, discrepancies between MP2 and CCSD(T) energetics tend to increase when there are qualitative differences in the hydrogen-bonding networks of the water clusters being studied. This review highlights the recent and exciting work in this area and provides an overview of popular strategies for generating reliable properties and benchmark quality energetics for water clusters with correlated wavefunction methods. C 2013 John Wiley & Sons, Ltd.

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Section: Strategies For Extending High-accuracy Methods To Larger Clumentioning

confidence: 99%

Wavefunction methods for the accurate characterization of water clusters

Howard

Tschumper

2013

WIREs Comput Mol Sci

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“…Notice; that because an atom cannot be both a QM and a MM atom, there is no self-term in ΔE PC (Q,q) of eqn (12). Also, the presence of pairs of disjoint sets of point charges (such as Q and q) makes it difficult to directly apply the simplification proposed by Sangster and Dixon for an uniform set of charges, e.g.…”

Section: Qm/mm Partition Of the Potential Energymentioning

confidence: 99%

“…However, the use of standard Ewald summation to compute the QM/MM electrostatic interactions is justified when high-level ab initio QM methods are used, since the latter spends several orders of magnitude more of computing time than the former. Using eqn (11)(12)(13)(14), the long-range electrostatic energy in eqn (8) can be rewritten as,…”

Section: Qm/mm Partition Of the Potential Energymentioning

confidence: 99%

Multiple active zones in hybrid QM/MM molecular dynamics simulations for large biomolecular systems

Torras

2015

Phys. Chem. Chem. Phys.

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A new QM/MM molecular dynamics approach that can deal with the dynamics of large real systems involving several simultaneous active zones is presented. Multiple, unconnected but interacting quantum regions are treated independently in an ordinary QM/MM approach but in a manner which converges to a unique simulation. The multiple active zones in the hybrid QM/MM molecular dynamics methodology (maz-QM/MM MD) involves molecular dynamics that is driving the whole simulation with several parallel executions of energy gradients within the QM/MM approach that merge into each MD step. The Ewald-summation method is used to incorporate long-range electrostatic interactions among the active zones in conjunction with periodic boundary conditions. To illustrate and ascertain capabilities and limitations, we present several benchmark calculations using this approach. Our results show that maz-QM/MM MD method is able to provide simultaneous treatment of several active zones of very large proteins such as the Cu-4His-ΔC* cage, a self-assembly of a 24-mer cage-like protein ferritin.

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“…However, continued theoretical advances will be necessary to accurately account for the effects of solvent or chemical environment, and additional improvements are necessary in approximations or algorithms to allow dynamics simulations of large molecules using accurate electronic structure methods. Mixed quantum-mechanics/ molecular-mechanics approaches, [172][173][174][175][176][177] are probably a necessary but not sufficient tool to enable the most challenging of these simulations. Recent work on effective fragment potential methods [178][179][180][181] may be helpful in this regard.…”

Section: 142mentioning

confidence: 99%