Potential model for iron-carbon incorporation covalent bonding effects. At time of publication this was the only potential which binds properly to vacancies and NOT to interstitials. This gives it the right energetics in a dislocation core, and at a surface. Good clustering of C behavior and fct martensite. Solution energy -7.13eV, migration energy 0.89eV (i.e. diffuses more slowly than vacancies). Compatible with Ackland-Mendelev '04 iron.