diff --git a/ao/lib/basis.ml b/ao/lib/basis.ml
index d1faf93..c464c2d 100644
--- a/ao/lib/basis.ml
+++ b/ao/lib/basis.ml
@@ -14,6 +14,20 @@ let not_implemented () =
   Util.not_implemented "Only Gaussian is implemented"
 
 
+let of_nuclei_and_basis_string ?(kind=`Gaussian) ?operators ?(cartesian=false)
+    ~nuclei filename =
+  match kind with
+  | `Gaussian ->
+      let basis =
+        Gaussian.Basis.of_nuclei_and_basis_string ~nuclei filename
+      in
+      let ao_basis =
+        Basis_poly.Gaussian (Basis_gaussian.make ~basis ?operators ~cartesian nuclei )
+      in
+      { ao_basis ; cartesian }
+  | _ -> not_implemented ()
+
+
 let of_nuclei_and_basis_filename ?(kind=`Gaussian) ?operators ?(cartesian=false)
     ~nuclei filename =
   match kind with
diff --git a/ao/lib/basis.mli b/ao/lib/basis.mli
index c632d5e..7b714e1 100644
--- a/ao/lib/basis.mli
+++ b/ao/lib/basis.mli
@@ -33,6 +33,35 @@ val b : Ao.Basis.t = Gaussian Basis, spherical, 15 AOs
 *)
 
 
+val of_nuclei_and_basis_string :
+  ?kind:[> `Gaussian ] ->
+  ?operators:Operator.t list ->
+  ?cartesian:bool ->
+  nuclei:Nuclei.t ->
+  string -> t
+(** Creates the data structure for the atomic orbitals basis from a
+    molecule ~Nuclei.t~ and a basis-set string.
+
+   Defaults:
+   - ~kind~ : ~`Gaussian~
+   - ~operators~ : ~[]~
+   - ~cartesian~ : ~false~
+
+   Example:
+   #+begin_example
+let b = Ao.Basis.of_nuclei_and_basis_string ~nuclei "
+HYDROGEN
+S  1
+  1        0.0395061728     1.00000000
+
+"
+;;
+val b : Ao.Basis.t = Gaussian Basis, spherical, 1 AOs
+   #+end_example
+
+*)
+
+
 (** Access *)
 
 val size : t -> int