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Sahu N, Khire SS, Gadre SR. Combining fragmentation method and high-performance computing: Geometry optimization and vibrational spectra of proteins. J Chem Phys 2023; 159:044309. [PMID: 37522406 DOI: 10.1063/5.0149572] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2023] [Accepted: 07/12/2023] [Indexed: 08/01/2023] Open
Abstract
Exploring the structures and spectral features of proteins with advanced quantum chemical methods is an uphill task. In this work, a fragment-based molecular tailoring approach (MTA) is appraised for the CAM-B3LYP/aug-cc-pVDZ-level geometry optimization and vibrational infrared (IR) spectra calculation of ten real proteins containing up to 407 atoms and 6617 basis functions. The use of MTA and the inherently parallel nature of the fragment calculations enables a rapid and accurate calculation of the IR spectrum. The applicability of MTA to optimize the protein geometry and evaluate its IR spectrum employing a polarizable continuum model with water as a solvent is also showcased. The typical errors in the total energy and IR frequencies computed by MTA vis-à-vis their full calculation (FC) counterparts for the studied protein are 5-10 millihartrees and 5 cm-1, respectively. Moreover, due to the independent execution of the fragments, large-scale parallelization can also be achieved. With increasing size and level of theory, MTA shows an appreciable advantage in computer time as well as memory and disk space requirement over the corresponding FCs. The present study suggests that the geometry optimization and IR computations on the biomolecules containing ∼1000 atoms and/or ∼15 000 basis functions using MTA and HPC facility can be clearly envisioned in the near future.
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Affiliation(s)
- Nityananda Sahu
- Theoretische Chemie, Philipps-Universität Marburg, 35032 Marburg, Germany
| | - Subodh S Khire
- RIKEN Center for Computational Science, Kobe 650-0047, Japan
| | - Shridhar R Gadre
- Departments of Scientific Computing, Modelling & Simulation and Chemistry, Savitribai Phule Pune University, Pune 411007, India
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Herman KM, Xantheas SS. An extensive assessment of the performance of pairwise and many-body interaction potentials in reproducing ab initio benchmark binding energies for water clusters n = 2-25. Phys Chem Chem Phys 2023; 25:7120-7143. [PMID: 36853239 DOI: 10.1039/d2cp03241d] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
We assess the performance of 7 pairwise additive (TIP3P, TIP4P, TIP4P-ice, TIP5P, OPC, SPC, SPC/E) and 8 families of many-body potentials (q-AQUA, HIPPO, AMOEBA, EFP, TTM, WHBB, MB-pol, MB-UCB) in reproducing high-level ab initio benchmark values, CCSD(T) or MP2 at the complete basis set (CBS) limit for the binding energy and the many-body expansion (MBE) of water clusters n = 2-11, 16-17, 20, 25. By including a large range of cluster sizes having dissimilar hydrogen bonding networks, we obtain an understanding of how these potentials perform for different hydrogen bonding arrangements that are mostly outside of their parameterization range. While it is appropriate to compare the results of ab initio based many-body potentials directly to the electronic binding energies (De's), the pairwise additive ones are compared to the enthalpies at T = 298 K, ΔH(298 K), as the latter class of force fields are parametrized to reproduce enthalpies (implicitly accounting for zero-point energy corrections) rather than binding energies. We find that all pairwise additive potentials considered overestimate the reference ΔH values for the n = 2-25 clusters by >13%. For the water dimer (n = 2) in particular, the errors are in the range 83-119% for the pairwise additive potentials studied since these are based on an effective rather than the true 2-body interaction specifically designed as a means of partially accounting for the missing many-body terms. This stronger 2-body interaction is achieved by an enhanced monomer dipole moment that mimics its increase from the gas phase monomer to the condensed phase value. Indeed, for cluster sizes n ≥ 4 the percent deviations become slightly smaller (albeit all exceeding 13%). In contrast, we find that the many-body potentials perform more accurately in reproducing the electronic binding energies (De's) throughout the entire cluster range (n = 2-25), all reproducing the ab initio benchmark binding energies within ±7% of the respective CBS values. We further assess the ability of a subset of the many-body potentials (MB-UCB, q-AQUA, MB-pol, and TTM2.1-F) to also reproduce the magnitude of the ab initio many-body energy terms for water cluster sizes n = 7, 10, 16 and 17. The potentials show an overall good agreement with the available benchmark values. However, we identify characteristic differences upon comparing the many-body terms at both the ab initio-optimized geometries and the respective potential-optimized geometries to the reference ab initio values. Additionally, by applying this analysis to a wide range of cluster sizes, trends in the MBE of the potentials with increasing cluster size can be identified. Finally, in an attempt to draw a parallel between the pairwise additive and many-body potentials, we report the analysis of the individual molecular dipole moments for water clusters with 1 to ∼4 solvation shells with the TTM2.1-F potential. We find that the internally solvated water molecules have in general a larger molecular dipole moment ranging from 2.6-3.0 D. This justifies the use of an enhanced, with respect to the gas-phase value, molecular dipole moment for the pairwise additive potentials, which is intended to fold in the many body terms into an effective (enhanced) pairwise interaction through the choice of the charges. These results have important implications for the development of future generations of efficient, transferable, and highly accurate classical interaction potentials in both the pairwise additive and many-body categories.
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Affiliation(s)
- Kristina M Herman
- Department of Chemistry, University of Washington, Seattle, WA 98195, USA.
| | - Sotiris S Xantheas
- Department of Chemistry, University of Washington, Seattle, WA 98195, USA. .,Advanced Computing, Mathematics and Data Division, Pacific Northwest National Laboratory, 902 Battelle Boulevard, P.O. Box 999, MS K1-83, WA, 99352, USA.
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Patkar D, Bharati Ahirwar M, Deshmukh MM. A Tug of War between the Self- and Cross-associating Hydrogen Bonds in Neutral Ammonia-Water Clusters: Energetic Insights by Molecular Tailoring Approach. Chemphyschem 2022; 23:e202200476. [PMID: 36127809 DOI: 10.1002/cphc.202200476] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2022] [Revised: 09/09/2022] [Indexed: 01/05/2023]
Abstract
In the present work, the energies of various types of individual HBs observed in neutral (NH3 )m (H2 O)n , (m+n=2 to 7) clusters were estimated using the molecular tailoring approach (MTA)-based method. The calculated individual HB energies suggest that the O-H…N HBs are the strongest (1.21 to 12.49 kcal mol-1 ). The next ones are the O-H…O (3.97 to 9.30 kcal mol-1 ) HBs. The strengths of N-H…N (1.09 to 5.29 kcal mol-1 ) and N-H…O (2.85 to 5.56 kcal mol-1 ) HBs are the weakest. The HB energies in dimers also follow this rank ordering. However, the HB energies in dimers are much smaller than those obtained by the MTA-based method due to the loss in cooperativity contribution in the dimers. Thus, the calculated cooperativity contributions, for different types of HBs, fall in the range 0.64 to 5.73 kcal mol-1 . We wish to emphasize based on the energetic rank ordering obtained by the MTA-based method that the O-H of water is a better HB donor than the N-H of ammonia. The reasons for the observed energetic rank ordering are two folds: (i) intrinsically stronger O-H…N HBs than the O-H…O ones as revealed by dimer energies and (ii) the higher cooperativity contribution in the former than the later ones. Indeed, the MTA-based method is useful in providing the missing energetic rank ordering of various type of HBs in neutral (NH3 )m (H2 O)n clusters, in the literature.
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Affiliation(s)
- Deepak Patkar
- Department of Chemistry, Dr. Harisingh Gour Vishwavidyalaya, (A Central University), 470003, Sagar, India
| | - Mini Bharati Ahirwar
- Department of Chemistry, Dr. Harisingh Gour Vishwavidyalaya, (A Central University), 470003, Sagar, India
| | - Milind M Deshmukh
- Department of Chemistry, Dr. Harisingh Gour Vishwavidyalaya, (A Central University), 470003, Sagar, India
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4
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Tzeli D, Xantheas SS. Breaking covalent bonds in the context of the many-body expansion (MBE). I. The purported "first row anomaly" in XH n (X = C, Si, Ge, Sn; n = 1-4). J Chem Phys 2022; 156:244303. [PMID: 35778077 DOI: 10.1063/5.0095329] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We present a new, novel implementation of the Many-Body Expansion (MBE) to account for the breaking of covalent bonds, thus extending the range of applications from its previous popular usage in the breaking of hydrogen bonds in clusters to molecules. A central concept of the new implementation is the in situ atomic electronic state of an atom in a molecule that casts the one-body term as the energy required to promote it to that state from its ground state. The rest of the terms correspond to the individual diatomic, triatomic, etc., fragments. Its application to the atomization energies of the XHn series, X = C, Si, Ge, Sn and n = 1-4, suggests that the (negative, stabilizing) 2-B is by far the largest term in the MBE with the higher order terms oscillating between positive and negative values and decreasing dramatically in size with increasing rank of the expansion. The analysis offers an alternative explanation for the purported "first row anomaly" in the incremental Hn-1X-H bond energies seen when these energies are evaluated with respect to the lowest energy among the states of the XHn molecules. Due to the "flipping" of the ground/first excited state between CH2 (3B1 ground state, 1A1 first excited state) and XH2, X = Si, Ge, Sn (1A1 ground state, 3B1 first excited state), the overall picture does not exhibit a "first row anomaly" when the incremental bond energies are evaluated with respect to the molecular states having the same in situ atomic states.
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Affiliation(s)
- Demeter Tzeli
- Laboratory of Physical Chemistry, Department of Chemistry, National and Kapodistrian University of Athens, Panepistimiopolis Zografou, Athens 15784, Greece
| | - Sotiris S Xantheas
- Advanced Computing, Mathematics and Data Division, Pacific Northwest National Laboratory, 902 Battelle Boulevard, P.O. Box 999, Mississippi K1-83, Richland, Washington 99352, USA
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Ahirwar MB, Gurav ND, Gadre SR, Deshmukh MM. Hydration Shell Model for Expeditious and Reliable Individual Hydrogen Bond Energies in Large Water Clusters. Phys Chem Chem Phys 2022; 24:15462-15473. [DOI: 10.1039/d2cp01663j] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Recently, we have developed and tested a method, based on the molecular tailoring approach (MTA-based) to directly estimate the individual hydrogen bond (HB) energies in molecular clusters. Application of this...
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Heindel JP, Xantheas SS. Molecular Dynamics Driven by the Many-Body Expansion (MBE-MD). J Chem Theory Comput 2021; 17:7341-7352. [PMID: 34723531 DOI: 10.1021/acs.jctc.1c00780] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We present a protocol for classical and nuclear quantum dynamics, in which the energies and forces are generated by the many-body expansion (MBE), and apply it to water clusters using the TTM2.1-F and MB-Pol interaction potentials at various temperatures. We carry out MBE-molecular dynamics (MD) classical and nuclear quantum dynamical simulations, in which the energies and forces of the full system are approximated by the two-, three-, and four-body terms of the MBE, and compare the average potential and the vibrational density of states with the full simulation, i.e., the one for which no MBE is used. Our results indicate that the thermally averaged potential energy from the MBE up to the four-body term converges with near-identical behavior to the one from the full simulation. The three-body makes a substantial contribution (∼20%) to the energy, whereas the four-body is necessary for obtaining quantitatively accurate energetics and forces, albeit making a small contribution to each (∼2%). We further show that the harmonic frequencies are reproduced to within a few wavenumbers (cm-1) at the four-body level and that the slowest modes to converge with the MBE rank are those involving the strongest hydrogen bonds. Anharmonicity exacerbates this effect, so that a four-body description of the energies and forces is needed to achieve accurate anharmonic vibrational frequencies in the hydrogen-bonded OH-stretching region. We also discuss the asymptotic scaling of the MBE-MD protocol with respect to the cost of the underlying potential energy evaluation, suggesting that electronic structure methods that scale at least as N4, N being the size of the system, are needed to result in savings over the traditional full MD simulation. We anticipate that the MBE-MD protocol can evolve into a powerful and practical method, which will allow for highly accurate ab initio MD simulations on a much broader range of molecular systems than can be currently handled.
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Affiliation(s)
- Joseph P Heindel
- Department of Chemistry, University of Washington, Seattle, Washington 98195, United States
| | - Sotiris S Xantheas
- Department of Chemistry, University of Washington, Seattle, Washington 98195, United States.,Advanced Computing, Mathematics and Data Division, Pacific Northwest National Laboratory, 902 Battelle Boulevard, P.O. Box 999, MS K1-83, Richland, Washington 99352, United States
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7
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Molecular Tailoring Approach for the Estimation of Intramolecular Hydrogen Bond Energy. Molecules 2021; 26:molecules26102928. [PMID: 34069140 PMCID: PMC8155843 DOI: 10.3390/molecules26102928] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2021] [Revised: 05/11/2021] [Accepted: 05/12/2021] [Indexed: 11/29/2022] Open
Abstract
Hydrogen bonds (HBs) play a crucial role in many physicochemical and biological processes. Theoretical methods can reliably estimate the intermolecular HB energies. However, the methods for the quantification of intramolecular HB (IHB) energy available in the literature are mostly empirical or indirect and limited only to evaluating the energy of a single HB. During the past decade, the authors have developed a direct procedure for the IHB energy estimation based on the molecular tailoring approach (MTA), a fragmentation method. This MTA-based method can yield a reliable estimate of individual IHB energy in a system containing multiple H-bonds. After explaining and illustrating the methodology of MTA, we present its use for the IHB energy estimation in molecules and clusters. We also discuss the use of this method by other researchers as a standard, state-of-the-art method for estimating IHB energy as well as those of other noncovalent interactions.
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Ahirwar MB, Gadre SR, Deshmukh MM. Direct and Reliable Method for Estimating the Hydrogen Bond Energies and Cooperativity in Water Clusters, W n, n = 3 to 8. J Phys Chem A 2020; 124:6699-6706. [PMID: 32786666 DOI: 10.1021/acs.jpca.0c05631] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
No direct method for estimating the individual O-H···O hydrogen bond (H-bond) energies in water clusters (Wn) exists in the literature. In this work, we propose such a direct method based on the molecular tailoring approach, which also enables the estimation of the cooperativity contributions. The calculated H-bond energies at MP2(full)/aug-cc-pVTZ and CCSD(T)/aug-cc-pVDZ levels for Wn, n = 3 to 8, agree well with one another and fall between 0.3 and 11.6 kcal mol-1 with the cooperativity contributions in the range of -1.2 and 7.0 kcal mol-1. For gauging the accuracy of our H-bond energies for a cluster, the H-bond energy sum is added to the sum of monomer energies, and the results are compared with the respective total energy. These two values agree with each other to within 8.3 mH (∼5 kcal mol-1), testifying the accuracy of our estimated H-bond energies. Further, these H-bond strengths show a good correlation with the respective O-H stretching frequencies and the molecular electron density values at the (3, -1) O-H···O H-bond critical point.
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Affiliation(s)
- Mini Bharati Ahirwar
- Department of Chemistry, Dr. Harisingh Gour Vishwavidyalaya (A Central University), Sagar 470003, India
| | - Shridhar R Gadre
- Interdisciplinary School of Scientific Computing and Department of Chemistry, Savitribai Phule Pune University, Pune 411 007, India
| | - Milind M Deshmukh
- Department of Chemistry, Dr. Harisingh Gour Vishwavidyalaya (A Central University), Sagar 470003, India
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9
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Manogaran D. Making and breaking of small water clusters: A combined quantum chemical and molecular dynamics approach. J Comput Chem 2019; 40:1556-1569. [DOI: 10.1002/jcc.25811] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2018] [Revised: 02/01/2019] [Accepted: 02/10/2019] [Indexed: 11/12/2022]
Affiliation(s)
- Dhivya Manogaran
- Solid State and Structural Chemistry UnitIndian Institute of Science Bangalore 560012 Karnataka India
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Naskar P, Roy R, Talukder S, Chaudhury P. Structural, spectroscopic and thermodynamic aspects of azide–water clusters: an approach using a conjugated prescription of stochastic and quantum chemical methods. Mol Phys 2018. [DOI: 10.1080/00268976.2018.1465605] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
Affiliation(s)
- Pulak Naskar
- Department of Chemistry, University of Calcutta, Kolkata, India
| | - Rituparna Roy
- Department of Chemistry, Indian Institute of Technology Bombay, Mumbai, India
| | - Srijeeta Talukder
- Department of Physical Chemistry, Indian Association for the Cultivation of Science, Kolkata, India
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11
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Holmes JD, Otero-de-la-Roza A, DiLabio GA. Accurate Modeling of Water Clusters with Density-Functional Theory Using Atom-Centered Potentials. J Chem Theory Comput 2017; 13:4205-4215. [DOI: 10.1021/acs.jctc.7b00624] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Jake D. Holmes
- Department
of Chemistry and ‡Faculty of Management, The University of British Columbia, 3247
University Way, Kelowna, British Columbia, Canada V1V 1V7
| | - Alberto Otero-de-la-Roza
- Department
of Chemistry and ‡Faculty of Management, The University of British Columbia, 3247
University Way, Kelowna, British Columbia, Canada V1V 1V7
| | - Gino A. DiLabio
- Department
of Chemistry and ‡Faculty of Management, The University of British Columbia, 3247
University Way, Kelowna, British Columbia, Canada V1V 1V7
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12
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Chen GD, Weng J, Song G, Li ZH. Generalized Switch Functions in the Multilevel Many-Body Expansion Method and Its Application to Water Clusters. J Chem Theory Comput 2017; 13:2010-2020. [DOI: 10.1021/acs.jctc.7b00144] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Affiliation(s)
- Guo Dong Chen
- Collaborative Innovation Center of Chemistry for Energy Material, Shanghai Key Laboratory of Molecular Catalysis & Innovative Materials, Department of Chemistry, Fudan University, Shanghai 200433, China
| | - Jingwei Weng
- Collaborative Innovation Center of Chemistry for Energy Material, Shanghai Key Laboratory of Molecular Catalysis & Innovative Materials, Department of Chemistry, Fudan University, Shanghai 200433, China
| | - Guoliang Song
- Collaborative Innovation Center of Chemistry for Energy Material, Shanghai Key Laboratory of Molecular Catalysis & Innovative Materials, Department of Chemistry, Fudan University, Shanghai 200433, China
| | - Zhen Hua Li
- Collaborative Innovation Center of Chemistry for Energy Material, Shanghai Key Laboratory of Molecular Catalysis & Innovative Materials, Department of Chemistry, Fudan University, Shanghai 200433, China
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Sahu N, Gadre SR. Vibrational infrared and Raman spectra of polypeptides: Fragments-in-fragments within molecular tailoring approach. J Chem Phys 2017; 144:114113. [PMID: 27004868 DOI: 10.1063/1.4943966] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
The present work reports the calculation of vibrational infrared (IR) and Raman spectra of large molecular systems employing molecular tailoring approach (MTA). Further, it extends the grafting procedure for the accurate evaluation of IR and Raman spectra of large molecular systems, employing a new methodology termed as Fragments-in-Fragments (FIF), within MTA. Unlike the previous MTA-based studies, the accurate estimation of the requisite molecular properties is achieved without performing any full calculations (FC). The basic idea of the grafting procedure is implemented by invoking the nearly basis-set-independent nature of the MTA-based error vis-à-vis the respective FCs. FIF has been tested out for the estimation of the above molecular properties for three isomers, viz., β-strand, 310- and α-helix of acetyl(alanine)nNH2 (n = 10, 15) polypeptides, three conformers of doubly protonated gramicidin S decapeptide and trpzip2 protein (PDB id: 1LE1), respectively, employing BP86/TZVP, M06/6-311G**, and M05-2X/6-31G** levels of theory. For most of the cases, a maximum difference of 3 cm(-1) is achieved between the grafted-MTA frequencies and the corresponding FC values. Further, a comparison of the BP86/TZVP level IR and Raman spectra of α-helical (alanine)20 and its N-deuterated derivative shows an excellent agreement with the existing experimental spectra. In view of the requirement of only MTA-based calculations and the ability of FIF to work at any level of theory, the current methodology provides a cost-effective solution for obtaining accurate spectra of large molecular systems.
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Affiliation(s)
- Nityananda Sahu
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur 208 016, India
| | - Shridhar R Gadre
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur 208 016, India
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Singh G, Nandi A, Gadre SR. Breaking the bottleneck: Use of molecular tailoring approach for the estimation of binding energies at MP2/CBS limit for large water clusters. J Chem Phys 2016; 144:104102. [PMID: 26979676 DOI: 10.1063/1.4943115] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
A pragmatic method based on the molecular tailoring approach (MTA) for estimating the complete basis set (CBS) limit at Møller-Plesset second order perturbation (MP2) theory accurately for large molecular clusters with limited computational resources is developed. It is applied to water clusters, (H2O)n (n = 7, 8, 10, 16, 17, and 25) optimized employing aug-cc-pVDZ (aVDZ) basis-set. Binding energies (BEs) of these clusters are estimated at the MP2/aug-cc-pVNZ (aVNZ) [N = T, Q, and 5 (whenever possible)] levels of theory employing grafted MTA (GMTA) methodology and are found to lie within 0.2 kcal/mol of the corresponding full calculation MP2 BE, wherever available. The results are extrapolated to CBS limit using a three point formula. The GMTA-MP2 calculations are feasible on off-the-shelf hardware and show around 50%-65% saving of computational time. The methodology has a potential for application to molecular clusters containing ∼100 atoms.
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Affiliation(s)
- Gurmeet Singh
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur 208016, India
| | - Apurba Nandi
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur 208016, India
| | - Shridhar R Gadre
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur 208016, India
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SHRIVASTAVA RAJAN, RAKSHIT AVIJIT, SHANKER SUDHANSHU, VIG LOVEKESH, BANDYOPADHYAY PRADIPTA. A combination of Monte Carlo Temperature Basin Paving and Graph theory: Water cluster low energy structures and completeness of search. J CHEM SCI 2016. [DOI: 10.1007/s12039-016-1135-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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16
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Sahu N, Singh G, Nandi A, Gadre SR. Toward an Accurate and Inexpensive Estimation of CCSD(T)/CBS Binding Energies of Large Water Clusters. J Phys Chem A 2016; 120:5706-14. [PMID: 27351269 DOI: 10.1021/acs.jpca.6b04519] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Owing to the steep scaling behavior, highly accurate CCSD(T) calculations, the contemporary gold standard of quantum chemistry, are prohibitively difficult for moderate- and large-sized water clusters even with the high-end hardware. The molecular tailoring approach (MTA), a fragmentation-based technique is found to be useful for enabling such high-level ab initio calculations. The present work reports the CCSD(T) level binding energies of many low-lying isomers of large (H2O)n (n = 16, 17, and 25) clusters employing aug-cc-pVDZ and aug-cc-pVTZ basis sets within the MTA framework. Accurate estimation of the CCSD(T) level binding energies [within 0.3 kcal/mol of the respective full calculation (FC) results] is achieved after effecting the grafting procedure, a protocol for minimizing the errors in the MTA-derived energies arising due to the approximate nature of MTA. The CCSD(T) level grafting procedure presented here hinges upon the well-known fact that the MP2 method, which scales as O(N(5)), can be a suitable starting point for approximating to the highly accurate CCSD(T) [that scale as O(N(7))] energies. On account of the requirement of only an MP2-level FC on the entire cluster, the current methodology ultimately leads to a cost-effective solution for the CCSD(T) level accurate binding energies of large-sized water clusters even at the complete basis set limit utilizing off-the-shelf hardware.
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Affiliation(s)
- Nityananda Sahu
- Department of Chemistry, Indian Institute of Technology Kanpur , Kanpur 208 016, India
| | - Gurmeet Singh
- Department of Chemistry, Indian Institute of Technology Kanpur , Kanpur 208 016, India
| | - Apurba Nandi
- Department of Chemistry, Indian Institute of Technology Kanpur , Kanpur 208 016, India
| | - Shridhar R Gadre
- Department of Chemistry, Indian Institute of Technology Kanpur , Kanpur 208 016, India
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17
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Sahu N, Gadre SR. Accurate vibrational spectra via molecular tailoring approach: a case study of water clusters at MP2 level. J Chem Phys 2016; 142:014107. [PMID: 25573553 DOI: 10.1063/1.4905004] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
In spite of the recent advents in parallel algorithms and computer hardware, high-level calculation of vibrational spectra of large molecules is still an uphill task. To overcome this, significant effort has been devoted to the development of new algorithms based on fragmentation methods. The present work provides the details of an efficient and accurate procedure for computing the vibrational spectra of large clusters employing molecular tailoring approach (MTA). The errors in the Hessian matrix elements and dipole derivatives arising due to the approximation nature of MTA are reduced by grafting the corrections from a smaller basis set. The algorithm has been tested out for obtaining vibrational spectra of neutral and charged water clusters at Møller-Plesset second order level of theory, and benchmarking them against the respective full calculation (FC) and/or experimental results. For (H2O)16 clusters, the estimated vibrational frequencies are found to differ by a maximum of 2 cm(-1) with reference to the corresponding FC values. Unlike the FC, the MTA-based calculations including grafting procedure can be performed on a limited hardware, yet take a fraction of the FC time. The present methodology, thus, opens a possibility of the accurate estimation of the vibrational spectra of large molecular systems, which is otherwise impossible or formidable.
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Affiliation(s)
- Nityananda Sahu
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur 208 016, India
| | - Shridhar R Gadre
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur 208 016, India
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Sahu N, Khire SS, Gadre SR. Structures, energetics and vibrational spectra of (H2O)32clusters: a journey from model potentials to correlated theory. Mol Phys 2015. [DOI: 10.1080/00268976.2015.1062150] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Raghavachari K, Saha A. Accurate Composite and Fragment-Based Quantum Chemical Models for Large Molecules. Chem Rev 2015; 115:5643-77. [PMID: 25849163 DOI: 10.1021/cr500606e] [Citation(s) in RCA: 183] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Krishnan Raghavachari
- Department of Chemistry, Indiana University, 800 E. Kirkwood Avenue, Bloomington, Indiana 47405, United States
| | - Arjun Saha
- Department of Chemistry, Indiana University, 800 E. Kirkwood Avenue, Bloomington, Indiana 47405, United States
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Zurheide F, Dierking CW, Pradzynski CC, Forck RM, Flüggen F, Buck U, Zeuch T. Size-Resolved Infrared Spectroscopic Study of Structural Transitions in Sodium-Doped (H2O)n Clusters Containing 10–100 Water Molecules. J Phys Chem A 2014; 119:2709-20. [DOI: 10.1021/jp509883m] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Florian Zurheide
- Institut für Physikalische Chemie, Tammannstaße
6, Georg-August-Universität Göttingen, D-37077 Göttingen, Germany
| | - Christoph W. Dierking
- Institut für Physikalische Chemie, Tammannstaße
6, Georg-August-Universität Göttingen, D-37077 Göttingen, Germany
| | - Christoph C. Pradzynski
- Institut für Physikalische Chemie, Tammannstaße
6, Georg-August-Universität Göttingen, D-37077 Göttingen, Germany
| | - Richard M. Forck
- Institut für Physikalische Chemie, Tammannstaße
6, Georg-August-Universität Göttingen, D-37077 Göttingen, Germany
| | - Florian Flüggen
- Institut für Physikalische Chemie, Tammannstaße
6, Georg-August-Universität Göttingen, D-37077 Göttingen, Germany
| | - Udo Buck
- Max-Planck-Institut für Dynamik und Selbstorganisation, Am Faßberg 17, D-37077 Göttingen, Germany
| | - Thomas Zeuch
- Institut für Physikalische Chemie, Tammannstaße
6, Georg-August-Universität Göttingen, D-37077 Göttingen, Germany
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