Abstract: | We have calculated the transition energies (ionization potential, excitation energies, electron affinity) of neutral lanthanum (La I) and singly ionized lanthanum (La II). The calculations are based upon the multiconfiguration Hartree-Fock (MCHF) method within the framework of Breit-Pauli relativistic corrections. These energies are important for determination of physical and chemical properties for La I and La II. Results obtained have been compared with other works. |