Measurement of evaporation residue excitation functions for the<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mmultiscripts><mml:mi>F</mml:mi><mml:mprescripts/><mml:none/><mml:mn>19</mml:mn></mml:mmultiscripts></mml:math>+<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mmultiscripts><mml:mi>Pt</mml:mi><mml:mprescripts/><mml:none/><mml:mrow><mml:mn>194</mml:mn><mml:mo>,</mml:mo><mml:mn>196</mml:mn><mml:mo>,</mml:mo><mml:mn>198</mml:mn></mml:mrow></mml:mmultiscripts></mml:math>reactions

Experimental measurements of evaporation residue (ER) cross sections for the $^{19}F$ + $^{194,196,198}\mathrm{Pt}$ reactions forming $^{213,215,217}\mathrm{Fr}$ compound nuclei are reported. The cross sections are measured at beam energies in the range of 101--137.3 MeV. The survival probability of the $^{213}\mathrm{Fr}$ compound nucleus with neutron number $N=126$ is found to be lower than the survival probabilities of $^{215}\mathrm{Fr}$ and $^{217}\mathrm{Fr}$ with neutron numbers $N=128$ and 130 respectively. Statistical model analysis of the ER cross sections show that an excitation energy dependent scaling of the finite-range rotating liquid drop model fission barrier is necessary to fit the experimental data. The fitted scaling factors for $^{213}\mathrm{Fr}$ are found to be smaller than those of $^{215}\mathrm{Fr}$ and $^{217}\mathrm{Fr}$ for almost the entire range of excitation energies.