Segmented basis

We turn now to the binding energy results obtained for Be4 [74], which are displayed in Table 5.5. The bond length was held fixed at 3.9 ao, which is the CCSD optimimum value in a large segmented basis set. There is a qualitative difference... 

Aim to gain scaie, reduce costs on a segment-by-segment basis > Change industry stnicture to own advantage... 

Knowles-Handy program to obtain full Cl energies for the first row atoms and their hydrides in 4s3pld/2slp basis sets these benchmarks were used to evaluate the CIPSI method219 and the performance of ANO basis sets versus more traditional segmented basis sets.247 Casanovas, Rubio, and Illas have also performed full Cl studies on the interaction of H atom with Cu5 and Ags cluster models to investigate the transferability of the correlation contribution to the chemisorption bond for different pseudopotentials.248... 

As discussed previously, FCI calculations for CH2 show that the CASSCF/MRCI treatment accurately accounts for the differential correlation contribution to the CHj Ai- Bi separation. In Table V, this level of treatment is performed using increasingly accurate ANO basis sets. It is interesting to note that although the [4s 3p 2d lf/3s 2p Id] basis set contains fewer contracted functions than the largest segmented basis sets previously applied to this problem, it produces a superior result for the separation. The largest... 

The shear relaxation modulus Gs t) and the first normal-stress difference function G i(t), both normalized on a per-segment basis and with kT set to 1, are obtained from the constitutive equation of the Rouse model (Eq. (7.55) with Sp replaced by Tp) as... 

The segment number r is, in general, different from the degree of polymerization or from the number of repeating units of a polymer chain but proportional to it. One should note that Equations [4.4.12 and 4.4.13] can be used on any segmentation basis, i.e., also with r = on a hard-core volume segmented basis and segment fractions instead of... 

A recent discussion of the g-function was made by Masegosa et al. Unfortunately, g-and X-functions were not always treated in a thermodynamically clear manner in the literature. Sometimes they were considered to be equal, and this is only true in the rare case of composition independence. Sometimes, and this is more dangerous, neglect or misuse of the underlying segmentation basis is formed. Thus, numerical data from literature has to be handled with eare (using the correct data from the reviews is therefore recommended). 

In implementations which are specialized for segmented basis sets it is usual to scale the integrals with the contraction coefficient in the initial stages of the computation. This simplifies the contraction step to a basic reduction. 

To give an example, in which the memory access will have a significant effect, consider the first half-transformation step. The following example is a general contraction, for a segmented basis set the transformation step is a simple reduction and should be executed immediately when the primitive integral is formed and resides in the cache. The conventional implementation is... 

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