Most often used for checking the MECI calculation and for teaching. MS=n overrides the normal choice of magnetic component of spin. Normally, if a triplet is requested, an MS of 1 will be used; this excludes all singlets. If MS=0 is also given, then singlets will also be calculated. For an odd-electron system, MS=-0.5 will give the same results as MS=0.5. The use of MS should not affect the values of the results at all.