arXiv subjects

O. A. Popova

Publications and source records attributed to O. A. Popova.

2 recordsLinked to original sources

arXiv2006

Comment on ``Sodium Pyroxene NaTiSi$_2$O$_6$: Possible Haldane Spin-1 Chain System''

Magnetic and electronic properties of NaTiSi$_2$O$_6$ in low temperature phase were studied in the framework of the LDA+U approximation. We stress that neglecting correlation effects in LSDA calculations one obtains not only several times smaller value of the band gap, but also fails to describe magnetic properties of NaTiSi$_2$O$_6$. Our LDA+U results confirm formation of singlet Ti-Ti dimers in low temperature phase of NaTiSi$_2$O$_6$ driven by corresponding orbital ordering [J. Phys. Soc. Jpn. 71, 1423 (2002)], but strongly disagree with the LSDA results and interpretations of Phys. Rev. Lett. 93, 036401 (2004).

cond-mat.str-el↗

arXiv2003

The theoretical simulation of optical properties of crystals with statistically disordered arrangement of atoms and atomic groups on the basis of point-dipole model

With using of point-dipole model the theoretical calculations of main refractive indices and orientation of indicatrix of 18 minerals are performed. The feature of studied minerals is the statistically disordered arrangement of CO3, SO4, SO2, PO4 groups and also separate ions. The optical characters of uniaxial minerals and orientation of indicatrix of orthorhombic and monoclinic minerals, obtained by results of calculations, agree with experimental definitions.

physics.optics↗