The symmetry-adapted perturbation theory (SAPT) that has the ability in decompo- sition of the total interaction energy into physically meaningful components is used to provide a more fundamental understanding of inte...The symmetry-adapted perturbation theory (SAPT) that has the ability in decompo- sition of the total interaction energy into physically meaningful components is used to provide a more fundamental understanding of intermolecular forces. This work was motivated by the diffi- culty of standard SAPT in computing the intermolecular interactions for large energetic dimer systems. SAPT based on Kohn-Sham orbitals (SAPT(DFT)) proves computationally efficient for these large systems, but has been shown to perform poorly for interaction energy components. The deficiencies of SAPT(DFT) result from wrong asymptotical behaviors of commonly used exchange-correlation potentials. To remove the deficiencies, two asymptotic corrections by means of van Leeuwen and Baerends (LB) model potential and Fermi-Amaldi (FA) type potential were applied into three small test systems comprising He2, HF2 and (N2)2 and a set of larger ni- tramide dimers at several separations. The results showed that when utilizing newly developed frequency-dependent density susceptibilities (FDDS) technique for computing dispersion energy, the FA asymptotic correction is very effective to circumvent these deficiencies in SAPT(DFT) and yields a good accuracy over the LB correction. The FA corrected SAPT(DFT) approach is capa- ble of correctly predicting all the quantitative trends in binding energies for all test cases and substantially reduces computational cost as compared with the standard SAPT calculations. The successful application of the approach to nitramide dimer demonstrates that it potentially pro- vides a good means to calculate accurately intermolecular forces in larger system such as en- ergetic systems.展开更多
用高精度量子化学CCSD(T)方法,优化C_6H_6…AgCl复合物几何结构,发现两种可能存在的构型,其中较稳定的一种具有Cs对称性,Cl-Ag指向苯环碳-碳键中心,另一种具有C6v对称性,Cl-Ag指向苯环中心,它们的结合能分别为-93 k J/mol和-69 k J/mol,...用高精度量子化学CCSD(T)方法,优化C_6H_6…AgCl复合物几何结构,发现两种可能存在的构型,其中较稳定的一种具有Cs对称性,Cl-Ag指向苯环碳-碳键中心,另一种具有C6v对称性,Cl-Ag指向苯环中心,它们的结合能分别为-93 k J/mol和-69 k J/mol,C_6H_6与AgCl的相互作用远大于C_6H_6与HCl的作用。SAPT对称匹配微扰理论能量分解分析结果显示,在C_6H_6与AgCl分子间的π…Ag相互作用中,诱导作用是主要的吸引作用,色散及静电作用的贡献较小,然而C_6H_6与HCl相互作用则是以静电和色散为主要的吸引作用。展开更多
Geometries, interaction energies and electronic properties for four types of dimers（hydrogen bonded, halogen bonded, π-halogen bonded, and ~r-hydrogen bonded） between HCCF and HCCR（R=F, CI, Br） were studied via M...Geometries, interaction energies and electronic properties for four types of dimers（hydrogen bonded, halogen bonded, π-halogen bonded, and ~r-hydrogen bonded） between HCCF and HCCR（R=F, CI, Br） were studied via MP2/6-31 1＋＋G（d,p） ab initio calculation. It is shown that the strength of the zr-hydrogen bonded dimers turns out to be greater than those of the other three types of dimers, with the interaction energies --4.611 kJ/mol for HCCF-HCCF, -4.700 kJ/mol for HCCF-HCCC1, and -4.850 kJ/mol for HCCF-HCCBr respectively at the CCSD（T）/6-311＋＋ G（d,p）//MP2/6-31 1＋＋G（d,p） level. In an effort to understand the nature of the intermolecular interactions prevalent in these dimers, the interaction energies were decomposed into physically distinct energy components with the aid of the symmetry adapted perturbation theory（SAPT）. The dispersion force is found to be the main origin of the intermolecular interactions in hydrogen bonded and halogen bonded dimers. In the π-halogen bonded system, the dispersion is the major bonding force in HCCF-HCCF and HCCF-HCCC1, while the induction energy is the most important component in HCCF-HCCBr. However, both the dispersion and electrostatic energy play a key role in π-hydrogen bonded dimers.展开更多
基金supported by the Institute of Chemical Materials(Grant No.42105080107)the National Natural Science Foundation of China(Grant Nos.10176012 and 20173028)China Academy of Engineering Physics(Grant No.2002z0501).
文摘The symmetry-adapted perturbation theory (SAPT) that has the ability in decompo- sition of the total interaction energy into physically meaningful components is used to provide a more fundamental understanding of intermolecular forces. This work was motivated by the diffi- culty of standard SAPT in computing the intermolecular interactions for large energetic dimer systems. SAPT based on Kohn-Sham orbitals (SAPT(DFT)) proves computationally efficient for these large systems, but has been shown to perform poorly for interaction energy components. The deficiencies of SAPT(DFT) result from wrong asymptotical behaviors of commonly used exchange-correlation potentials. To remove the deficiencies, two asymptotic corrections by means of van Leeuwen and Baerends (LB) model potential and Fermi-Amaldi (FA) type potential were applied into three small test systems comprising He2, HF2 and (N2)2 and a set of larger ni- tramide dimers at several separations. The results showed that when utilizing newly developed frequency-dependent density susceptibilities (FDDS) technique for computing dispersion energy, the FA asymptotic correction is very effective to circumvent these deficiencies in SAPT(DFT) and yields a good accuracy over the LB correction. The FA corrected SAPT(DFT) approach is capa- ble of correctly predicting all the quantitative trends in binding energies for all test cases and substantially reduces computational cost as compared with the standard SAPT calculations. The successful application of the approach to nitramide dimer demonstrates that it potentially pro- vides a good means to calculate accurately intermolecular forces in larger system such as en- ergetic systems.
文摘用高精度量子化学CCSD(T)方法,优化C_6H_6…AgCl复合物几何结构,发现两种可能存在的构型,其中较稳定的一种具有Cs对称性,Cl-Ag指向苯环碳-碳键中心,另一种具有C6v对称性,Cl-Ag指向苯环中心,它们的结合能分别为-93 k J/mol和-69 k J/mol,C_6H_6与AgCl的相互作用远大于C_6H_6与HCl的作用。SAPT对称匹配微扰理论能量分解分析结果显示,在C_6H_6与AgCl分子间的π…Ag相互作用中,诱导作用是主要的吸引作用,色散及静电作用的贡献较小,然而C_6H_6与HCl相互作用则是以静电和色散为主要的吸引作用。
基金Supported by the Scientific Research Fund of Hunan Provincial Education Department(No.B30865)Research Foundation of Hunan University of Science and Technology,China(No.E50814)
文摘Geometries, interaction energies and electronic properties for four types of dimers（hydrogen bonded, halogen bonded, π-halogen bonded, and ~r-hydrogen bonded） between HCCF and HCCR（R=F, CI, Br） were studied via MP2/6-31 1＋＋G（d,p） ab initio calculation. It is shown that the strength of the zr-hydrogen bonded dimers turns out to be greater than those of the other three types of dimers, with the interaction energies --4.611 kJ/mol for HCCF-HCCF, -4.700 kJ/mol for HCCF-HCCC1, and -4.850 kJ/mol for HCCF-HCCBr respectively at the CCSD（T）/6-311＋＋ G（d,p）//MP2/6-31 1＋＋G（d,p） level. In an effort to understand the nature of the intermolecular interactions prevalent in these dimers, the interaction energies were decomposed into physically distinct energy components with the aid of the symmetry adapted perturbation theory（SAPT）. The dispersion force is found to be the main origin of the intermolecular interactions in hydrogen bonded and halogen bonded dimers. In the π-halogen bonded system, the dispersion is the major bonding force in HCCF-HCCF and HCCF-HCCC1, while the induction energy is the most important component in HCCF-HCCBr. However, both the dispersion and electrostatic energy play a key role in π-hydrogen bonded dimers.
