The atomic nuclei with exotic neutron/proton ratio are the subject of a great part of actual nuclear physics researches, as well for the means of their synthesis - they are difficult to create - as for their interpretation. In this thesis, the neutron rich nuclei of the A=100 mass region have been created, at high spin, using a particular heavy ions reaction, the induced fission. The produced nuclei have been identified, one by one, through their gamma radiation measured via the multidetector EUROBALL III. Some characteristics of this production mode, taken from our data, are discussed. The precise gamma-spectroscopy of some neutron rich Technetium (A = 103) and Silver (A = 111, 113, 115) isotopes is presented. The underlying proton orbitals are identified through the role they play in the structure of the excitation bands of odd-A nuclei of this mass region (Technetium, A from 97 up to 107; Rhodium, A from 105 up to 111 ; Silver A from 107 up to 115). An interpretation for these odd-Z nuclei is proposed, using also the results of a rotor plus quasiparticle code and some self-consistent microscopic calculations. These nuclei are indeed a sensitive test for these models, the main ingredients of which are taken from results on some few nuclei lying in the valley of stability.
