The decay luminescence curves (Fig. , curves 1, 2) can be better characterized by considering them as a sum of two exponentials with lifetimes of 1.0 and 4.0 ms. The relative contribution of the long-lived or short-lived components in the total intensity of Yb 3+ luminescence varies depending on the detection frequency. In the YScO3 crystal structure, Yb 3+ optical centers with a lifetime of τ = 1.0 ms are formed when Yb 3+ substitutes of Y 3+ in the C2 site. The intensity of the short-lived component increases when registering the decay kinetics of Yb 3+ luminescence on the line belonging to the long-lived center (νdet. = 9737 cm -1 ). This increase is caused by the overlap of the luminescence bands with peaks of νmax. = 9737 cm -1 and 9625 cm -1 . This overlapping leads to a combined effect on the luminescence intensity, resulting in a change in the relative contribution of the short-lived component. On the other hand, when the detection frequency is νdet = 8985 cm -1 , the decay kinetics of Yb 3+ luminescence can be accurately described by a single exponential decay law (Fig. , curve 1). This detection band corresponds to a long-lived optical center with a lifetime of τ = 4.0 ms. This long-lived center is formed when Yb 3+ substitutes with Y 3+ in the C3i site. The difference in lifetimes of the two short-lived centers is due to the difference in ionic radii of Y 3+ (0.87 Å) and Sc 3+ (0.75 Å), which are replaced by Yb 3+ (1.01 Å) in the C2 site. The substitution of yttrium or scandium ions in the lattice with ytterbium ion leads to a change in the distance between the cation and its oxygen environment in the distorted octahedron . Decreasing the distance between the impurity center and its oxygen environment lead to changes in the crystal field parameters that are responsible for the probabilities of radiative transitions . Therefore, the optical center with a lifetime of 0.620 ms is attributed to the substitution of Sc 3+ with C2 site symmetry in the YScO3 crystal lattice for Yb 3+ , and the optical center being formed due to the substitution of Y 3+ with C2 site symmetry in the YScO3 crystal lattice for Yb 3+ has a longer lifetime (1.0 ms).