So, here are our two identical H atoms. So, this is a one s Atomic orbital of the first H atom and the second Atomic orbital of the second H atom. So we have an electron in each atomic orbital. So, if we combine two Atomic orbitals according to quantum mechanics, we're going to form two molecular orbitals. One will be the phi B, which is the Bonding molecular orbital. And the second will be the phi A, which is the Anti Bonding molecular orbital.