	for ( i = 0; i < molecularDynamics->numberOfAtoms; i++)
	{
		gdouble speed = maxwel(molecularDynamics->forceField->molecule.atoms[i].prop.masse,temperature);
		getRandVect(speed, molecularDynamics->velocity[i]);
		for ( j = 0; j < 3; j++)
			C[j] += molecularDynamics->velocity[i][j];
	}
