Abstract
The real Hilbert space formalism developed within the quaternionic quantum mechanics (HQM) is fully applied to the simple model of the autonomous particle. This framework permits novel insights within the usual description of the complex autonomous particle, particulaly concening the energy of a non-stationary motion. Through the appraisal of the physical role played by a fully quaternionic scalar potential, a original self-interaction within the quaternionic autonomous particle has been determined as well. Scattering processes are considered to illustrate these novel features.