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  • Elias Theodore, Simos, +59 authors A Zdetsis
  • 2007
Aims and Scope The major goal of the Journal of Computational Methods in Sciences and Engineering (JCMSE) is the publication of new research results on computational methods in sciences and engineering. Common experience had taught us that computational methods originally developed in a given basic science, e.g. physics, can be of paramount importance to(More)
A linear-scaling implementation of the elongation cutoff technique (ELG/C) that speeds up Hartree-Fock (HF) self-consistent field calculations is presented. The cutoff method avoids the known bottleneck of the conventional HF scheme, that is, diagonalization, because it operates within the low dimension subspace of the whole atomic orbital space. The(More)
Current state of development of the elongation method originally proposed by Imamura is presented. Recent progress in methodology, including geometry optimization and employment of the fast multiple method, is highlighted. The accuracy and efficiency of the elongation method as compared to exact canonical Hartree-Fock and Kohn-Sham approaches are discussed.(More)
The performance of the Message Passing Interface collective communication algorithms is a critical issue widely discussed in both academia and industry. In order to achieve and maintain high performance in the MPI implementations even in regard to random system behavior, the collective operations must be adapted to both the cluster platform and the workload(More)
A simple way to improve the accuracy of the fragmentation methods is proposed. The formalism was applied to the elongation (ELG) method at restricted open-shell Hartree-Fock (ROHF) level of theory. The α-helix conformer of polyglycine was taken as a model system. The modified ELG method includes a simplified electrostatic field resulting from point-charge(More)
The extension of the elongation method into description of electron correlation effects at ab intio level is presented. The formalism and implementation of the elongation-MP2 methodology is discussed. The results of calculations for model systems are presented to illustrate efficiency and accuracy of the method. Directions of the further development are(More)
The static (hyper)polarizabilities of the dimer and trimer with diffuse excess electrons, [Li(+)[calix[4]pyrrole]Li(-)](n), are firstly investigated by the DFT(B3LYP) method in detail. For the dimer and trimer, a Li atom inside each calix[4]pyrrole unit is ionized to form a diffuse excess electron. The results show that the dimer and trimer containing two(More)
A new kind of solvated electron systems, sphere-shaped e(-)@C60F60 (I(h)) and capsule-shaped e(-)@C60F60 (D6h), in contrast to the endohedral complex M@C60, is represented at the B3LYP/6-31G(d) + dBF (diffusive basis functions) density functional theory. It is proven, by examining the singly occupied molecular orbital (SOMO) and the spin density map of(More)