Link between EPR g-factors and local structure of the orthorhombic Ce3+ center in Y3Al5O12 and Lu3Al5O12 garnets

► EPR g-factors of orthorhombic Ce3+ center in YAG and LuAG garnets explained reasonably. ► Local structure around Ce3+ ion in YAG and LuAG garnets obtained and compared with those calculated by first principles. ► Intrinsic discontinuity of perturbation formulae shown explicitly.