Using hydrodynamic simulations we investigate the time evolution and fragmentation of regions within molecular clouds which have lost their turbulent support leading to gravitational contraction .
The initial density distributions are described by random Gaussian fluctuations with varying slopes \nu of the power spectrum P ( k ) \propto k ^ { - \nu } , covering the range from flat ( \nu = 0 ) to very steep spectra ( \nu = 3 ) .
We consider molecular cloud volumes containing different masses relative to the average Jeans mass M _ { J } , from 1 M _ { J } to 222 M _ { J } .
This parameter study extends the detailed analysis of systems with initially P ( k ) \propto k ^ { -2 } and mass 222 M _ { J } presented by Klessen & Burkert ( 2000 ) .

The dynamical evolution of the simulated molecular cloud regions is insensitive to the slope of the initial density fluctuation spectrum .
The system evolves into a complex network of intersecting filaments and collapsing clumps leading to the formation of a compact cluster of accreting and interacting embedded protostellar cores .
The cluster builds up as bound entity , but dissolves later due to collisional effects .
In all simulations , the mass spectrum of collapsed cores is very broad , has approximately log-normal shape and peaks roughly at the average Jeans mass .
This supports the hypothesis that the average Jeans mass is the main parameter determining the peak in the stellar spectrum , and suggests that the interplay between self-gravity on the one side and thermal and turbulent pressure on the other side is the dominant process that regulates the formation of stellar clusters .