  Besides right choice of entrance channel, selection of optimal beam energies
for synthesis of superheavy elements plays a crucial role. A thorough
investigation with the advanced statistical and dinuclear system models on all
the experiments performed for the synthesis of the successful superheavy
elements Z=104-118 and failed superheavy elements Z=119-120 leads us to infer
that improper choice of the beam energies may be responsible for too low
production cross sections to measure and thus the cause for the debacle. We
have predicted the optimal beam energies to obtain the maximum production cross
sections for all the reactions used for the superheavy elements Z=104-120. Hope
exploitation of these predictions may be on the cards soon to extend the
periodic table for the eighth period
