Response function in gas-drop nuclear model

Response function to periodical external field, strength function and its momenta have been obtained in semiclassical approximation of a gas-drop model. The model used is based on the method of boundary conditions provided on dynamic effective surface (ES) of a nucleus. ES is determined as position of nucleon density gradient maxima. Frequences of isoscalar multipole giant resonances (as volumetric density oscillations) are connected with oscillations of nucleus surface layer. Two models are considered: zero sound (0 sound)+ES and the first sound +ES, corresponding to different types of volumetric density oscillations. Common conclusion has been drawn: independent of the type of volumetric oscillations in side nucleus the lowest resonances mainly exhausted energetically weighted sum. Results obtained in the (o sound)+ES model agree well with experiment