Absolute hardness of phenanthrene doped anthracene single crystals by Knoop indentation technique

The absolute hardness value of anthracene doped with phenanthrene using Knoop hardness technique has been obtained. The absolute hardness is defined as the hardness which is not load dependent. The results obtained by graphical analysis compare well with the calculated results, within experimental error. The present note reports the results obtained, using the method utilizing the extrapolation function. The higher absolute hardness of the phenanthrene doped anthracene is due to the molecular hindrance to slip.