Complete basis set limit ofAb initiobinding energies and geometrical parameters for various typical types of complexes

Abstract

Using basis-set extrapolation schemes for a given data set, we evaluated the binding energies and geometries at the complete basis set (CBS) limit at the levels of the second order Møller-Plesset perturbation theory (MP2) and the coupled cluster theory with singles, doubles, and perturbative triples excitations [CCSD(T)]. The systems include the hydrogen bonding (water dimer), aromatic interaction (benzene dimer), pi-H interaction (benzene-water), cation-water, anion-water, pi-cation interaction (cation-benzene), and pi-anion interaction (anion-triazine). One extrapolation method is to exploit both BSSE-corrected and BSSE-uncorrected binding energies for the aug-cc-pVNZ (N = 2, 3, 4, ...) basis set in consideration that both binding energies give the same CBS limit (CBS(B)). Another CBS limit (CBS(C)) is to use the commonly known extrapolation approach to exploit that the electron correlation energy is proportional to N(-3). Since both methods are complementary, they are useful for estimating the errors and trend of the asymptotic values. There is no significant difference between both methods. Overall, the values of CBS(C) are found to be robust because of their consistency. However, for small N (in particular, for N = 2, 3), CBS(N)(B) is found to be slightly better for water-water interactions and cation-water and cation-benzene interactions, whereas CBS(N)(C) is found to be more reliable for bezene-water and anion-water interactions. We also note that the MP2 CBS limit value based on N = 2 and 3 combined with the difference between CCSD(T) and MP2 at N = 2 would be exploited to obtain a CCSD(T)/CBS value for aromatic-aromatic interactions and anion-pi interactions, but not for cationic complexes.

A methodological analysis for the assessment of non-covalent π interactions

“…However when we use the core valence basis set for Na, for either ACVQZ' or ACVQZ methods, a very reasonable equilibrium distance of 2.375 Å is obtained, with a binding energy (À24.48 kcal/mol) close to the AVTZ value (-21.75 kcal/mol, Table 1). Furthermore, the CCSD(T)/AVTZ binding energy for this new geometry (À22.56 kcal/mol) is also quite similar to the CCSD(T)/AVTZ//RI-MP2/AVTZ value (À21.85 kcal/mol), the reference data (À22.90 kcal/mol) [43] and the experimental binding energy (22.1 ± 1.4 kcal/mol) [42] (see Table 1). Therefore, from these results an improvement in both geometry and binding energies can be observed for complex 2 when using the cc-pCVQZ (instead of the cc-pVQZ or aug-cc-pVQZ basis sets) for Na.…”

“…methodology: MP2/6-311+G(2d,2p)//MP2/6-311+G*. b Ref [43],. methodology: CCSD(T)/CBS//MP2/CVDZ+aVDZ.…”

Phenylacetylene: A Hydrogen Bonding Chameleon

“…In a few cases CCSD(T)/CBS limit energies were estimated with the extrapolation scheme utilizing the fact that the electron correlation error is proportional to N À3 for the aug-cc-pVNZ basis set series. [47,48] The CCSD(T)/CBS energies were estimated by assuming that the difference in binding energies between MP2/ aug-cc-pVDZ and MP2/CBS calculations is similar to that between CCSD(T)/aug-cc-pVDZ and CCSD(T)/CBS calculations. The thermochemical calculations were based on the ideal gas, rigid rotor, and harmonic oscillator approximations.…”

Induction‐Driven Stabilization of the Anion–π Interaction in Electron‐Rich Aromatics as the Key to Fluoride Inclusion in Imidazolium‐Cage Receptors

“…Computational: High-level ab initio coupled-cluster with single and double and perturbative triple/complete basis set (CCSD(T)/CBS) [39] results show that the interaction energies of F À with benzene (Bz) and triethylbenzene (Et 3 Bz) are 0.7 and À0.9 kcal mol À1 , respectively (Table 1). Energy component analysis using symmetry-adapted perturbation theory (SAPT) [40,41] reveals that the Bz À F À and Et 3 Bz À F À complexes have large negative quadrupole moments, and their electrostatic energies (% + 6 kcal mol À1 ) and exchange energies (+ 4 and 6 kcal mol As the second p system is added to a complex in which the p system interacts with F À (i.e., as the Et 3 Bz À F À complex changes to the (Et 3 Bz) 2 À F À complex), the latter sandwiched system is highly stabilized with a greatly enhanced interaction energy (À4.3 kcal mol À1 ; cf.…”

“…The complete basis set (CBS) limit values for the RIMP2 interaction energies were evaluated based on the extrapolation method by exploiting the fact that the basis set error in the electron correlation energy is proportional to N À3 for the aug-cc-pVNZ (or aVNZ) basis set. [39] The CCSD(T)/CBS interaction energies were estimated by calculating the sum of CCSD(T)/aVDZ interaction energies and the difference between the RIMP2/CBS and RIMP2/aVDZ interaction energies. Meanwhile, the CCSD(T)/CBS interaction energies of (Bz) 2 ÀF À /A C H T U N G T R E N N U N G (Et 3 Bz) 2 ÀF À complexes were estimated as the sum of the MP2/CBS interaction energy and twice the [CCSD(T)/CBS-MP2/CBS] energy for the respective BzÀF À /Et 3 BzÀ F À complexes.…”