For I-(H 2 O) 4 cluster, it has long believed that the C 4 symmetry structure is most stable isomer at low temperature. However, calculated vibrational spectra values using ab initio disagree with experimental values. Therefore, we calculated the structure of I-(H 2 O) 4 using extensive ab initio calculation. Hence, we found most stable isomer for I-(H 2 O) 4 at low temperature. The isomer has ...

We perform ab initio calculations for nuclei around 16O, 40Ca, and 56Ni using realistic nucleon-nucleon forces. In particular, 56Ni is computed as the heaviest nucleus in this kind of ab initio calculation. Ground-state and single-particle energies including three-body-cluster effects are obtained within the framework of the unitary-model-operator approach. It is shown that the CD-Bonn nucleon-...

We present a new linear scaling ab initio total energy electronic structure calculation method based on a divide-and-conquer strategy. This method is simple to implement, easy to parallelize, and produces accurate results when compared with direct ab initio methods. The new method has been tested on nanosystems with up to 15 000 atoms using up to 8000 processors. (Some figures in this article a...

Tetrahydrobenzo[b]pyran derivatives 1 were utilized for the synthesis of several new pyrano[2,3-d]pyrimidine derivatives 2. Compound 2 was obtained in the presence of Ac2O/H2SO4 (as a catalyst) and was confirmed by spectroscopic data such as IR, 1H NMR and 13C NMR. Ab initio calculation was carried out to study geometric optimization, t...