Spin-component-scaled method

J. Hill and J. Platts, /. Chem. Theo. Comput., 3, 80 (2007). Spin-Component Scaling Methods... 

Hill, J. G., Platts, J. A. (2007). Spin-component scaling methods for weak and stacking interactions. Journal of Chemical Theory and Computation, 3, 80-85. 

Studying chiroptical properties can lead to novel ligand design. Mori et al. [214] considered four multiarmed chiral aryl ethers in diverse aromatic skeletons. Two of the molecules, (35) for example, were synthesized with the intent to lock the structure into one of two low-energy conformers. Structures were optimized with dispersion-corrected DFT at the BLYP/TZVP level of theory. Single point energy calculations were performed with a spin component scaled MP2 method and the TZVPP basis. CD spectra were calculated with BHLYP/TZVP. The asymmetric... 

Kozuch and Martin have proposed combining the double hybrid method with the SCS-MP2 treatment along with a dispersion correction. This so-called DSD-DFT method (dispersion corrected, spin-component-scaled double hybrid) has the exchange-correlation term... 

Grimme, S. Goaigk, L. Fink, R. F. Spin-component-scaled electron correlation methods, WlREs Comput. Mol. Sci. 2012,2, 886-906. 

J. Antony and S. Grimme, Is spin-component scaled second-order Mpller-Plesset perturbation theory an appropriate method for the study of noncovalent interactions in molecules J. Phys. Chem. A, 111 (2007) 4862-4868. 

Several other spin-component-scaled MP2 methods have been proposed, and spin-component scaling has also been applied to the CC method see S. Grimme et al., WIREs, Comput. Mol. ScL, 2, 886 (2012) for a review. 

Just as one can use spin-component scaling to improve the performance of MP2, one can multiply the contribution of the same-spin terms to the CCSD energy by an empirical parameter and multiply the contribution of the opposite-spin terms by another parameter. This gives the SCS-CCSD method [T. Takatani et al., J. Chem. Phys., 128,124111 (2008)]. The same-spin and opposite-spin parameter values 1.13 and 1.27, respectively, were found by fitting a set of known reaction energies. SCS-CCSD performs quite well for intermo-lecular interactions. 

Cremer, D. and He, Z. (1996) Sixth-order Moller-Plesset perturbation theory on the convergence of the MPn series. J. Phys. Chem., 100, 6173-6188. Grimme, S., Goerigk, L., and Fink, R.F. (2012) Spin-component-scaled electron correlation methods. Wiley Interdiscip. Rev. Comput. Mol Sci., 2, 886-906. Schwabe, X. and Grimme, S. (2008) Xheoretical thermodynamics for... 

Improvement of the Coupled-Cluster Singles and Doubles Method via Scaling Same- and Opposite-Spin Components of the Double Excitation Correlation Energy. 

The phase diagram of Fig. 30 looks very similar to the one measured for the solutions of linear and branched PI in CH and shown in Fig. 31. For these experiments, the originally synthesized branched material (PI of Fig. 29) was to a large extent freed from the linear components by means of the large-scale method of spin fractionation [73]. Despite the fact that the boundary between the homogeneous and the two-phase area was only mapped, instead of the usual cloud point measurements, the results of Fig. 31 testily to the existence of shape-induced incompatibility of polymers. It is remarkable that this phenomenon can be observed for comparatively low molar masses of the components. 

Jung et al. [81] reported a variant of this approach that used the multiplicative factor of zero for the SS component and 1.3 for the OS component. This calculation, SOS-MP2 (scaled opposite-spin MP2), can be performed with only an 0(n4) operation cost when combined with Almlof s Laplace transform technique [82], The SOS approximation can be applied to CIS(D) [69], A similar simplification was often adopted in the GW method under the name COHSEX approximation [32] also partly from an operation cost consideration. 

As reviewed in the previous section, measurements of Ti and Tip can provide an estimation of the length scale of miscibility of polymer blends. Compared with such kinds of experiments, the results of the spin-diffusion experiments are more quantitative and straightforward. The accuracy of the results of spin-diffusion experiments relies, to a large extent, on the values of spin-diffusion coefficients (7)) employed in calculation of the constituent phase components. Despite efforts that have been made, there still lacks a suitably applicable method of directly measuring the spin-diffusion coefficients, at least for polymers. For rigid polymer below Tg, 0.8 nm /ms has been turned out to be a reliable value of spin-diffusion coefficient. The difficulty left then concerns how to determine the coefficient of the mobile phase, which is very sample dependent. Recently, through studies on diblock copolymers and blend samples with known domain sizes, Mellinger et al established empirical relations between the T2 and D as follows ... 

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