Spatial assignment of symmetry adapted perturbation theory interaction energy components: The atomic SAPT partition

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Today's quantum chemistry methods are extremely powerful but rely upon complex quantities such as the massively multidimensional wavefunction or even the simpler electron density. Consequently, chemical insight and a chemist's intuition are often lost in this complexity leaving the results obtained difficult to rationalize. To handle this overabundance of information, computational chemists have developed tools and methodologies that assist in composing a more intuitive picture that permits better understanding of the intricacies of chemical behavior. In particular, the fundamental comprehension of phenomena governed by non-covalent interactions is not easily achieved in terms of either the total wavefunction or the total electron density, but can be accomplished using more informative quantities. This perspective provides an overview of these tools and methods that have been specifically developed or used to analyze, identify, quantify, and visualize non-covalent interactions. These include the quantitative energy decomposition analysis schemes and the more qualitative class of approaches such as the Non-covalent Interaction index, the Density Overlap Region Indicator, or quantum theory of atoms in molecules. Aside from the enhanced knowledge gained from these schemes, their strengths, limitations, as well as a roadmap for expanding their capabilities are emphasized. ©2017Author(s

Section: Discussionmentioning

confidence: 99%

Perspective: Found in translation: Quantum chemical tools for grasping non-covalent interactions

Pastorczak¹,

Corminbœuf²

2017

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102

“…[21][22][23][24] In these approaches, the dispersion term is obtained using the frequency dependent density susceptibility function of time dependent DFT (TD-DFT). The perturbation theory of intermolecular interactions can accurately predict the complete intermolecular potential energy surfaces for weakly bound molecular complexes.…”

Section: Introductionmentioning

confidence: 99%

Chemical accuracy from quantum Monte Carlo for the benzene dimer

Azadi

Cohen

2015

We report an accurate study of interactions between benzene molecules using variational quantum Monte Carlo (VMC) and diffusion quantum Monte Carlo (DMC) methods. We compare these results with density functional theory using different van der Waals functionals. In our quantum Monte Carlo (QMC) calculations, we use accurate correlated trial wave functions including three-body Jastrow factors and backflow transformations. We consider two benzene molecules in the parallel displaced geometry, and find that by highly optimizing the wave function and introducing more dynamical correlation into the wave function, we compute the weak chemical binding energy between aromatic rings accurately. We find optimal VMC and DMC binding energies of −2.3(4) and −2.7(3) kcal/mol, respectively. The best estimate of the coupled-cluster theory through perturbative triplets/complete basis set limit is −2.65(2) kcal/mol [Miliordos et al., J. Phys. Chem. A 118, 7568 (2014)

“…Note that the intramolecular developments considered in this manuscript stem from two previous installments of our work on intermolecular interactions: atomic SAPT (A-SAPT) 8 and functional group SAPT (F-SAPT). 9 The former developed an effective two-body partition of SAPT, allowing one to parti- tion SAPT to the level of atom-pairwise intermolecular interactions.…”

mentioning

confidence: 99%

Communication: Practical intramolecular symmetry adapted perturbation theory via Hartree-Fock embedding

Parrish

Gonthier

Corminbœuf

et al. 2015

Self Cite

We develop a simple methodology for the computation of symmetry-adapted perturbation theory (SAPT) interaction energy contributions for intramolecular noncovalent interactions. In this approach, the local occupied orbitals of the total Hartree-Fock (HF) wavefunction are used to partition the fully interacting system into three chemically identifiable units: the noncovalent fragments A and B and a covalent linker C. Once these units are identified, the noninteracting HF wavefunctions of the fragments A and B are separately optimized while embedded in the HF wavefunction of C, providing the dressed zeroth order wavefunctions for A and B in the presence of C. Standard two-body SAPT (particularly SAPT0) is then applied between the relaxed wavefunctions for A and B. This intramolecular SAPT procedure is found to be remarkably straightforward and efficient, as evidenced by example applications ranging from diols to hexaphenyl-ethane derivatives.