In-core methods

The program can use conventional, in-core, or direct integral evaluation. The default ah initio algorithm checks the disk space and memory available. It then uses an in-core method if sufficient memory is available. If memory is not available for in core evaluation, the program uses a conventional method if... 

By de ult, Gaussian will substitute the in-core method for direct SCF when there is enough memory because it is fester. When we ran these computations, we explicitly prevented Gaussian from using the in-core method. When you run your jobs, however, the in-core method will undoubtedly be used for some jobs, and so your values may differ. An in-core job is identified by the following line in the output Two-electron integrals will be kept in memory. 

TUtegrals was the only option. Modem machines often have quite significant amounts off memory, a few Gbytes is not uncommon. For small and medium sized systems it may be possible to store all the integrals in the memory instead of on disk. Such in-core methods are very efficient for performing an HF calculation. The integrals are only calculated once, and each SCF iteration is just a multiplication of the integral tensor... 

Another method to synthesize hollow nanocapsules involves the use of nanoparticle templates as the core, growing a shell around them, then subsequently removing the core by dissolution [30-32]. Although this approach is reminiscent of the sacrificial core method, the nanoparticles are first trapped and aligned in membrane pores by vacuum filtration rather than coated while in aqueous solution. The nanoparticles are employed as templates for polymer nucleation and growth Polymerization of a conducting polymer around the nanoparticles results in polymer-coated particles and, following dissolution of the core particles, hollow polymer nanocapsules are obtained. 

Although sophisticated methods may constitute the core methods for certification it is useful to include good, well executed routine methods. In order to further minimize systematic error, a conscious purposeful attempt should be made to get methods and procedures with wide-ranging and different sample preparation steps, including no decomposition as in instrumental neutron activation analysis and particle induced X-ray emission spectrometry. 

Application of the equivalent cores method to solid compounds is slightly more complicated, requires additional assumptions, and is therefore less accurate than the application to gaseous compounds. However, fairly good correlations have been obtained for solid compounds of boron, carbon, nitrogen, and iodine20. The correlations were restricted, because of the nature of the assumptions involved, to molecular compounds or to compounds in which the core-ionized atoms are in anions. 

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