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In an attempt to understand the dynamics of collapsing starless cores, wehave onducted a detailed investigation of the velocity fields of two collapsingcores, L694-2 and L1197, with high spatial resolution HCN J=1-0 maps and MonteCarlo radiative transfer alculation.  It is found that infall motion is most active in the middle and outer layersoutside the central density-flat region, while both the central and outermostparts of the cores are static or exhibit slower motion. Their peak velocitiesare 0.28 km s^{-1} for L694-2 and 0.20 km s^{-1$ for L1197, which could not befound in simple models. These velocity fields are roughly consistent with thegravitational collapse models of the isothermal core; However, the velocitygradients inside the peak velocity position are steeper than those of themodels.  Our results also show that the density distributions are ~ r^{-2.5} and ~r^{-1.5} in the outer part for L694-2 and L1197, respectively. HCN abundancerelative to H_2 is spatially almost constant in L694-2 with a value of 7.0 X10^{-9}, while for L1197, it shows a slight inward increase from 1.7 X 10^{-9}to 3.5 X 10^{-9}.Comment: accepted in Ap

Velocity Distribution of Collapsing Starless Cores, L694‐2 and L1197