The molecular dynamic simulations have been performed on microsystem of liq
uid Co between 1873K and 300K; The pair distributed function and the change
of atomic group at differetent temperratures have been obtained by the EAM
method; If the cooling rate is low, the crystal would be formed. If the co
oling rate is very high, the amorphism would occur. It is obvious that the
ordering degree of liquid Co is strengthened with the temperature decrease.
The last result of simulation has been discussed by the pair analysis tech
nique. The various bond pairs in liquid Co are the basic units when they so
lidify. The micro configuration in liquid can be described by the bond pair
s. When the liquid Co forms crystal, the pairs 1421 and 1422 play an import
ant role. The inclination of changes of 1551 and 1541 is in accordance with
the liquid and amorphism.