shifts dctcrmincd from a n~icroscopic doublc-folding optical potcntial, rnarkcd improvement in thc and cxpcrimcnt, for clastic carbon-carbon scattcring bctwccn 200 and 300 McV, is obtainccl whcn nuclcon-nucleon slope paramctcr, appropriatc for diffractivc scattcring, are uscd. Thc appropriatcncss of thc pcrturbativc cikonal expansion is discussed by comparison with rcccnt rcsults, obtaincd for thc samc potentials, using a morc cxact cornplcx Wcntzcll-Kran~crs-Brillouin (WKB) formalism.En utilisant dcs ddphasagcs iconaux ddtcrminds h partir d'un potcnticl optiquc microscopiquc ii doublc rcpli, on obticnt unc amdlioration rnarqudc dc I'accord cntrc thCoric ct cxpdricncc. pour la diffusion dlastiquc carbonc-carbonc cntrc 200 ct 300 MeV. si I'on utilisc. pour Ic parametrc dc pcntc nucldon-nuclcon, sculcmcnt lcs valcurs appropridcs ii la diffusion diffractivc. La pcrtincncc du dCvcloppcmcnt iconal pcrturbatif cst discutCc, cn comparaison avcc dcs rdsultats rdccnts obtcnus ii partir du memc potcnticl cn utilisant un formalisrnc Wcntzcll-Kramcrs-Brillouin (WKB) cornplcxc plus cxact.