(** Information related to electrons. *)

type t = {
  n_alpha      : int ;  (** Number of alpha electrons *)
  n_beta       : int ;  (** Number of beta  electrons *)
  multiplicity : int ;  (** Spin multiplicity: 2S+1 *)
}


val make : ?multiplicity:int -> ?charge:int -> Nuclei.t -> t
(** Creates the data relative to electrons for a molecular system
  described by {!Nuclei.t} for a given total charge and spin multiplicity.
  @param multiplicity default is 1
  @param charge default is 0
  @raise Invalid_argument if the spin multiplicity is not compatible with
    the molecule and the total charge.
  *)

val charge : t -> Charge.t
(** Sum of the charges of the electrons. *)