Hi Minh,
If you don’t mind a little self-promotion, might I recommend the following articles:
J A Zimmerman, E B Webb III, J J Hoyt, R E Jones, P A Klein and D J Bammann, “Calculation of stress in atomistic simulation”, Modelling Simul. Mater. Sci. Eng. 12 (2004) S319–S332
Edmund B. Webb III, Jonathan A. Zimmerman and Steven C. Seel, “Reconsideration of Continuum Thermomechanical Quantities in Atomic Scale Simulations”, Mathematics and Mechanics of Solids 13: 221–266, 2008
Jonathan A. Zimmerman, Reese E. Jones and Jeremy A. Templeton, “A material frame approach for evaluating continuum variables in atomistic simulations”, Journal of Computational Physics 229 (2010) 2364–2389
Regards,
Jon Zimmerman