DYNAMICAL EFFECTS PRIOR TO HEAVY ION FUSION

Dynamical effects in the initial phase of fusion reactions are studied following the evolution of two colliding 100 Mo ions. The role of elastic forces associated with the Fermi-surface deformation is shown by comparing the results obtained with and without taking the memory effects into account. The Bass barrier separating fused and scattered congurations and the lower bound for the extra push energy are estimated. Examples of cases are shown in which the excitation energy and deformation dependence of the friction parameter arectitious and simulate the effects of collective motion related with the Fermi-surface deformations. ˆ§EI OE¸O ¤¨´ ³¨I¥¸±¨¥ OEE¥±EO ´ ´ I ²O´µ° ¸E ¤¨¨ ·¥ ±I¨¨ ¸²¨O´¨O ´ ¶·¨³¥·¥ ¸Eµ²±´µ- ¢¥´¨O ¤¢EI ¨µ´µ¢ 100 Mo. '· ¢´¥´¨¥³ ·¥§E²OE Eµ¢, ¶µ²EI¥´´OI ¸ EI¥Eµ³ OEE¥±Eµ¢ ¶ ³OE¨ ¨ i¥§ ¨I EI¥E , ¶µ± § ´ ·µ²O E¶·E£¨I ¸¨², ¸¢O§ ´´OI ¸ ¤¥Eµ·³ I¨¥° ¶µ¢¥·I´µ¸E¨ "¥·³¨. " ¥E¸O µI¥´± ´¨|´¥° £· ´¨IO O´¥·£¨¨ O±¸E· ¶EI ¨ i ·O¥· � ¸¸ , · §¤¥²OOÐ¥£µ ±µ´E¨£E· I¨¨, ¶·¨¢µ¤OШ¥ ± ¸²¨O´¨O ¨ ± · ¸¸¥O´¨O. �·¨¢¥¤¥´O ¶·¨³¥·O, ¢ ±µE µ·OI § ¢¨¸¨³µ¸EO ¶ · ³¥E· E·¥´¨O µE O´¥·- £¨¨ ¢µ§iE|¤¥´¨O ¨ ¤¥Eµ·³ I¨¨ O¢²O¥E¸O E¨§¨I¥¸±¨ ´¥ µiµ¸´µ¢ ´´µ° ¨ ¶µ¤³¥´O¥E ¸µiµ° OEE¥±EO ±µ²²¥±E¨¢´µ£µ ¤¢¨|¥´¨O, ¢O§¢ ´´O¥ ¤¥Eµ·³ I¨¥° ¶µ¢¥·I´µ¸E¨ "¥·³¨.