Romanian Reports in Physics, Vol. 68, No. 1, P. 169–176, 2016 ON THE COULOMB-EXCITATION ANALYSIS FOR MEDIUM AND HEAVY NUCLEI C. MĂNĂILESCU “Horia Hulubei” National Institute for Physics and Nuclear Engineering, P.O.Box MG-6, RO-077125 Bucharest-Magurele, Romania, E-mail: cristian.manailescu@nipne.ro Received July 23, 2014 Abstract. The cross sections for nuclear reactions are generally consider to be well known in spite of many reactions for which the data are conflicting or incomplete to make the validation of different model calculations possible. The Coulomb-excitation process has been used for decades to obtain information related to the low-lying nuclear states. Besides the several hundreds of new observed states, the most important contribution of the Coulomb-excitation process has been the information obtained on electromagnetic transition rates between nuclear states. An analysis of the Coulomb-excitation cross sections for a series of medium and heavy nuclei is given in the present paper in order to eventually improve an alpha-particle optical potential. Key words: Coulomb-excitation, nuclear reactions, cross-section. 1. INTRODUCTION Coulomb excitation (CE) is the excitation of the target nucleus in the electromagnetic field of the projectile, or vice versa. In the past, this process has been extensively used to study the first excited 2 + states of even-even nuclei. For pure CE, where the nuclei stay outside the range of the strong force, the excitation cross section can be expressed in terms of the same multipole matrix elements that characterize the γ decay of excited nuclear states. Therefore, a determination of the CE cross section leads directly to the determination of basic nuclear structure information. The CE process, as outlined below, is well understood, and results are largely model independent. Keeping the bombarding energy below the Coulomb barrier ensures that no nuclear excitation can take place. 2. EXCITATION CROSS SECTION As stated in the early years of CE experiments, a good approximation consist in assuming that the relative motion of the projectile follows a Rutherford trajectory, and the cross section for exciting a definite state |f > from a state |i > is