**Author details**

Ilmars Zalite<sup>1</sup> \*, Gundega Heidemane<sup>1</sup> , Janis Grabis1 and Mikhail Maiorov2

\*Address all correspondence to: ilmars.zalite@rtu.lv

1 Institute of Inorganic Chemistry, Riga Technical University, Riga, Latvia

2 Institute of Physics, University of Latvia, Salaspils, Latvia
