Only one hole is allowed in the RAS1 space during core excited state calculations and to ensure that the excitation of electron happens from the 1s orbitals, the orbital was kept frozen during the RASSCF optimization. Scalar relativistic correction effects have been included using second order Douglas-Kroll-Hess Hamiltonian and the calculations are performed with the following basis sets: ANO-RCC-VTZP is assigned on Fe, Mn, Co, N, Cl, and P and ANO-RCC-VDZP on C and H. For the RASPT2 calculations, an imaginary shift of 5.4 eV is employed without applying any IPEA shift.