Abstract
Masses of 130 open clusters in the Milky Way were used to estimate the frequency distribution of the masses of open clusters, F(Mc). The relation between the initial mass function, IMF, of massive stars and the relative mean luminosity function of 42 young open clusters are discussed. It was found that the slope of F(Mc) is different when it is evaluated in the inner and outer part of the solar circle. If this statistical evidence is added to other observational features, then it would indicate that the process of cluster formation would cause the observed variation in the IMF. In particular, deriving the stellar mass spectra for 42 open clusters and combining its slope with that of F(Mc), observational results may be obtained indicating galactocentric variations in IMF for massive stars.
