Dear Sir,
I have a couple of doubts regarding the conversion of Lammps Real units to SI units.

The units for Force in lammps real units is Kcal/moleAngstrom. I got some information from a website (http://openmopac.net/manual/pressure.html) that
1 GPa = 6.0221367/(4.184*10)kcal / (mol.Angstrom^3) = 0.14393kcal.mol1.Angstrom^3
Is this true? Can we use this conversion for converting the lammps real units of force to SI units of force. 
The second doubt is regarding the units for stress in lammps real units. Should we derive the units for stress based on the units of force? I aslo saw that the units for pressure in Lammps real units is Atmosphere. So should we take the units for stress as the same units for pressure?
Any help would be greatly appreciated.
Thanking you
Yours Sincerely
Ajay