Sorry... still there is a bug in the parallelisation of KERMODE and DIPOLE part of the imd code. Details of the bug: when atom moves from one cpu to another cpu, instead of resetting DP_E_IND value to zero, it is getting accumulated which results an error in the dipole convergence because of the dp_sum_global is getting more than 500. Status Now: the bug is solved and tested for differenct configurations (52488 atoms - using 2 to 216 processors)- it seems everything is working fine now