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QCaml/Utils/Electrons.ml

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2018-02-23 18:44:31 +01:00
(** Number of alpha and beta electrons *)
type t = {
n_alpha : int ;
n_beta : int ;
multiplicity : int;
}
let make ?multiplicity:(multiplicity=1) ?charge:(charge=0) nuclei =
let positive_charges =
Array.fold_left (fun accu (e, _) -> accu + Charge.to_int (Element.to_charge e) )
0 nuclei
in
let negative_charges = charge - positive_charges in
let n_elec = - negative_charges in
let n_beta = ((n_elec - multiplicity)+1)/2 in
let n_alpha = n_elec - n_beta in
let result = { n_alpha ; n_beta ; multiplicity } in
if multiplicity <> (n_alpha - n_beta)+1 then
invalid_arg "Electrons.make";
result