Cover Page

Fragmentation

Toward Accurate Calculations on
Complex Molecular Systems


Edited by

Mark S. Gordon

Iowa State University, USA











Wiley Logo

List of Contributors

Emily A. Carter

School of Engineering and Applied Science, Princeton University, USA

Garnet K.L. Chan

Frick Chemistry Laboratory, Department of Chemistry, Princeton University, USA

Ajitha Devarajan

Office of University Development, University of Michigan, USA

Johannes M. Dieterich

Department of Mechanical and Aerospace Engineering, Princeton University, USA

Dmitri G. Fedorov

Research Center for Computational Design of Advanced Functional Materials (CD-FMat), National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Japan

Alexander Gaenko

Advanced Research Computing, University of Michigan, USA

Kandis Gilliard

Department of Chemistry, University of Illinois at Urbana–Champaign, USA

Mark S. Gordon

Ames Laboratory of United States Department of Energy, USA

Department of Chemistry, Iowa State University, USA

Pradeep K. Gurunathan

Department of Chemistry, Purdue University, USA

Xiao He

School of Chemistry and Molecular Engineering, East China Normal University, China

NYU-ECNU Center for Computational Chemistry, NYU Shanghai, China

So Hirata

Department of Chemistry, University of Illinois at Urbana–Champaign, USA

Jan H. Jensen

Department of Chemistry, University of Copenhagen, Denmark

Carlos A. Jiménez-Hoyos

Frick Chemistry Laboratory, Department of Chemistry, Princeton University, USA

K. V. Jovan Jose*

Department of Chemistry, Indiana University, USA

Murat Keçeli

Department of Chemistry, University of Illinois at Urbana–Champaign, USA

Argonne National Laboratory, USA

Kazuo Kitaura

Graduate School of System Informatics, Kobe University, Japan

Christoph Köppl

Institute for Theoretical Chemistry, University of Stuttgart, Germany

Caroline M. Krauter

Department of Mechanical and Aerospace Engineering, Princeton University, USA

Jinjin Li

Department of Chemistry, University of Illinois at Urbana–Champaign, USA

National Key Laboratory of Science and Technology on Micro/Nano Fabrication, Department of Micro/Nano Electronics, Shanghai Jiao Tong University, China

Jinfeng Liu

School of Chemistry and Molecular Engineering, East China Normal University, China

Qianli Ma

Institute for Theoretical Chemistry, University of Stuttgart, Germany

Hiromi Nakai

Department of Chemistry and Biochemistry, School of Advanced Science and Engineering, Waseda University, Japan

Krishnan Raghavachari

Department of Chemistry, Indiana University, USA

Michael A. Salim

Department of Chemistry, University of Illinois at Urbana–Champaign, USA

Max Schwilk

Institute for Theoretical Chemistry, University of Stuttgart, Germany

Lyudmila V. Slipchenko

Department of Chemistry, Purdue University, USA

Olaseni Sode

Department of Chemistry, University of Illinois at Urbana–Champaign, USA

Department of Chemistry, Biochemistry, and Physics, The University of Tampa, USA

Casper Steinmann

Department of Physics, Chemistry and Pharmacy, University of Southern Denmark, Denmark

Hans-Joachim Werner

Institute for Theoretical Chemistry, University of Stuttgart, Germany

Theresa L. Windus

Ames Laboratory of United States Department of Energy, USA

Department of Chemistry, Iowa State University, USA

Sebastian Wouters

Center for Molecular Modelling, Ghent University, Belgium

Frick Chemistry Laboratory, Department of Chemistry, Princeton University, USA

Kiyoshi Yagi

Department of Chemistry, University of Illinois at Urbana–Champaign, USA

Theoretical Molecular Science Laboratory, RIKEN, Japan

Takeshi Yoshikawa

Department of Chemistry and Biochemistry, School of Advanced Science and Engineering, Waseda University, Japan

Kuang Yu

Department of Mechanical and Aerospace Engineering, Princeton University, USA

John Z. H. Zhang

School of Chemistry and Molecular Engineering, East China Normal University, China

NYU-ECNU Center for Computational Chemistry, NYU Shanghai, China

Department of Chemistry, New York University, USA

Tong Zhu

School of Chemistry and Molecular Engineering, East China Normal University, China

NYU-ECNU Center for Computational Chemistry, NYU Shanghai, China

Note

Preface

Electronic structure theory, also referred to as ab initio quantum chemistry (QC), has attained a high level of maturity and reliability for gas-phase molecules of modest size. Unfortunately, the formal scaling of these methods such as Hartree–Fock (HF), density functional theory (DFT), second-order perturbation theory (MP2), coupled cluster theory (CC), and multi-reference (MR) methods hinder their application to large molecules, to condensed phase systems or to excited electronic state potential energy surfaces. These limitations are especially severe for methods that account for electron correlation, such as MP2, CC, and MR methods, since their scaling with system size is steeper than for the simpler HF and DFT methods. There is therefore a need for computational strategies that nearly retain the accuracy of the most reliable methods while greatly reducing the scaling of these methods as a function of system size. While researchers who are interested in simulations of large molecular systems have often turned to classical molecular mechanics (MM) force fields, MM methods are limited in their applicability. While there are a few exceptions, classical MM cannot realistically treat bond making/bond breaking (the essence of chemistry) or excited state phenomena.

One effective QC approach that has become increasingly popular is referred to as fragmentation (broadly defined) or embedding theory. Fragmentation commonly refers to the physical subdivision of a large molecule into fragments, each of whose energy can be computed on a different compute node, thereby making the overall computation highly parallel. Fragmentation methods of this type scale nearly linearly with system size and can take advantage of massively parallel computers. Fragmentation methods of this type are discussed in Chapters 3, 5, 6, 7, 10, and 11. An alternative approach to physical fragmentation of a molecule is to fragment the wave function, by employing localized molecular orbitals to separate the wave function into domains that can be separately correlated. This approach is based on the fact that electron correlation is short-range. Chapter 1 provides an excellent discussion of local electron correlation methods by one of the leaders in the field.

Embedding methods are similar to fragmentation methods in that a total system is partitioned into multiple subsystems, in a manner that allows the incorporation of interactions among the subsystems. Like fragmentation and local orbital approaches, embedding methods reduce the steep scaling of traditional electronic structure methods. Embedding methods frequently involve multiple levels of theory. Approaches to embedding methods are discussed in Chapters 2, 4, 8, and 9.

The methods that are discussed in this book provide an exciting path forward to the accurate study of large molecules and condensed phase phenomena.