Dear Bhupendra Wakankar, You can use parallel version of the PC GAMESS to perform QC calculations on NT clusters. See the PC GAMESS homepages at MSU http://classic/gran/gamess/index.html http://quantum-2.chem.msu.ru/gran/gamess/index.html and at ISU http://www.msg.ameslab.gov/GAMESS/pcgamess.shtml Best regards Alex Granovsky