Toward the Exact Solution of the Electronic Schrödinger Equation for Noncovalent Molecular Interactions: Worldwide Distributed Quantum Monte Carlo Calculations

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• 作者：Martin Korth ; Arne L&uuml ; chow ; Stefan Grimme
• 刊名：Journal of Physical Chemistry A
• 出版年：2008
• 出版时间：March 13, 2008
• 年：2008
• 卷：112
• 期：10
• 页码：2104 - 2109
• 全文大小：181K
• 年卷期：v.112,no.10(March 13, 2008)
• ISSN：1520-5215

文摘

Quantum Monte Carlo (QMC) calculations on the stacked (st) and Watson/Crick (wc) bound adenine/thymine(A/T) and cytosine/guanine (C/G) DNA base pair complexes were made possible with the first large scaledistributed computing project in ab initio quantum chemistry, Quantum Monte Carlo at Home (QMC@HOME).The results for the interaction energies (wc-A/T = 15.7 kcal/mol, wc-C/G = 30.2 kcal/mol, st-A/T = 13.1kcal/mol, st-C/G = 19.6 kcal/mol) are in very good agreement with the best known coupled-cluster basedestimates. The accuracy of these values is further supported by calculations on the S22 benchmark set ofnoncovalently bound systems, for which we obtain a small mean absolute deviation of 0.68 kcal/mol. Ourresults support previous claims that the stacking energies are of comparable magnitude to the interactions ofthe commonly discussed hydrogen-bonded motif. Furthermore, we show that QMC can serve as anadvantageous alternative to conventional wave function methods for large noncovalently bound systems. Wealso investigated in detail all technical parameters of the QMC simulations and recommend a carefuloptimization procedure of the Jastrow correlation factors in order to obtain numerically stable and reliableresults.