Paramagnetic resonance of Cr$^{4+}$ и Mn$^{2+}$ ions in a Li$_{2}$CaSiO$_{4}$ crystal

Tetragonal Cr$^{4+}$ centers ($3d^2$ electron configuration, spin $S$ = 1) in the Li$_{2}$CaSiO$_{4}$ crystal at different frequencies were detected and studied. The value of splitting at a zero magnetic field was determined. In the area where the positions of the two Cr$^{4+}$ transitions coincide, the additional signal with inverse phase was observed. For uncontrolled impurity Mn$^{2+}$ ions ($S$ = $I$ = 5/2) the spin Hamiltonian parameters and localization are determined