Question
The mwfn filetype includes fields for alpha and beta electrons/orbitals/density matrices.
What is the definition of alpha and beta electrons; what distinguishes them?
For future research, where is this definition typically recorded?
Clues:
- Orbitals are recorded as either $\alpha$, $\beta$, or $\alpha+\beta$.
- $\beta$ orbitals implicitly come after $\alpha$ orbitals in indexing (with $n$ basis functions, the $i$th $\beta$ orbital is $n$ ahead of the $i$th $\alpha$ orbital. Do they overlap, or do $\alpha$ orbitals stop at $n$?).