diff --git a/configure.ac b/configure.ac
index ffc8572..266dfdd 100644
--- a/configure.ac
+++ b/configure.ac
@@ -22,7 +22,13 @@ PKG_LIBS=""
 PKG_CFLAGS=""
 # Checks for programs.
 AC_PROG_CC
+AC_PROG_CC_C_O
+
 AC_PROG_FC
+AC_FC_FREEFORM
+AC_FC_SRCEXT([f90])
+
+AC_PROG_FC_C_O
 AC_PROG_INSTALL
 AC_PROG_LN_S
 AC_PROG_CC_C99
diff --git a/src/templates_front/templator_front.org b/src/templates_front/templator_front.org
index dd8d503..bd292c1 100644
--- a/src/templates_front/templator_front.org
+++ b/src/templates_front/templator_front.org
@@ -723,6 +723,8 @@ end interface
    | ~$group_dset_dtype_double$~   | Double precision type of the dataset [C]       | ~double~           |
    | ~$group_dset_f_dtype_single$~ | Single precision type of the dataset [Fortran] | ~real(4)~          |
    | ~$group_dset_f_dtype_double$~ | Double precision type of the dataset [Fortran] | ~real(8)~          |
+   | ~$group_dset_f_dims$~         | Dimensions in Fortran                          | ~(:,:)~            |
+   
 
    Note: parent group name is always added to the child objects upon
    construction of TREXIO (e.g. ~num~ of ~nucleus~ group becomes
@@ -1301,7 +1303,7 @@ interface
    integer function trexio_write_$group$_$group_dset$_64 (trex_file, dset) bind(C)
      use, intrinsic :: iso_c_binding
      integer(8), intent(in), value :: trex_file
-     $group_dset_f_dtype_double$, intent(in) :: dset(*)
+     $group_dset_f_dtype_double$, intent(in) :: dset$group_dset_f_dims$
    end function trexio_write_$group$_$group_dset$_64
 end interface
      #+end_src
@@ -1311,7 +1313,7 @@ interface
    integer function trexio_read_$group$_$group_dset$_64 (trex_file, dset) bind(C)
      use, intrinsic :: iso_c_binding
      integer(8), intent(in), value :: trex_file
-     $group_dset_f_dtype_double$, intent(out) :: dset(*)
+     $group_dset_f_dtype_double$, intent(out) :: dset$group_dset_f_dims$
    end function trexio_read_$group$_$group_dset$_64
 end interface
      #+end_src
@@ -1321,7 +1323,7 @@ interface
    integer function trexio_write_$group$_$group_dset$_32 (trex_file, dset) bind(C)
      use, intrinsic :: iso_c_binding
      integer(8), intent(in), value :: trex_file
-     $group_dset_f_dtype_single$, intent(in) :: dset(*)
+     $group_dset_f_dtype_single$, intent(in) :: dset$group_dset_f_dims$
    end function trexio_write_$group$_$group_dset$_32
 end interface
      #+end_src
@@ -1331,7 +1333,7 @@ interface
    integer function trexio_read_$group$_$group_dset$_32 (trex_file, dset) bind(C)
      use, intrinsic :: iso_c_binding
      integer(8), intent(in), value :: trex_file
-     $group_dset_f_dtype_single$, intent(out) :: dset(*)
+     $group_dset_f_dtype_single$, intent(out) :: dset$group_dset_f_dims$
    end function trexio_read_$group$_$group_dset$_32
 end interface
      #+end_src
@@ -1341,7 +1343,7 @@ interface
    integer function trexio_write_$group$_$group_dset$ (trex_file, dset) bind(C)
      use, intrinsic :: iso_c_binding
      integer(8), intent(in), value :: trex_file
-     $group_dset_f_dtype_double$, intent(in) :: dset(*)
+     $group_dset_f_dtype_double$, intent(in) :: dset$group_dset_f_dims$
    end function trexio_write_$group$_$group_dset$
 end interface
      #+end_src
@@ -1351,7 +1353,7 @@ interface
    integer function trexio_read_$group$_$group_dset$ (trex_file, dset) bind(C)
      use, intrinsic :: iso_c_binding
      integer(8), intent(in), value :: trex_file
-     $group_dset_f_dtype_double$, intent(out) :: dset(*)
+     $group_dset_f_dtype_double$, intent(out) :: dset$group_dset_f_dims$
    end function trexio_read_$group$_$group_dset$
 end interface
      #+end_src
diff --git a/tools/generator.py b/tools/generator.py
index 1e004e3..8fe740a 100644
--- a/tools/generator.py
+++ b/tools/generator.py
@@ -312,6 +312,12 @@ for fname in files_funcs_dsets:
                         templine1 = templine2.replace('$group$', grname)
                         templine2 = templine1.replace('$GROUP$', grname.upper())
 
+                        if "$group_dset_f_dims$" in templine2:
+                            dims = "(" + ",".join([":" for _ in range(params['rank'])]) + ")"
+                            if dims == "()": dims = ""
+                            templine1 = templine2.replace("$group_dset_f_dims$", dims)
+                            templine2 = templine1
+
                         f_out.write(templine2)
                     else:
                         f_out.write(line)
diff --git a/trex.json b/trex.json
index a2448b8..5c2f8f8 100644
--- a/trex.json
+++ b/trex.json
@@ -23,7 +23,7 @@
 
     "ecp": {
         "lmax_plus_1"        : [ "int"  , [ "nucleus.num"                            ] ]
-      , "z_core"             : [ "int"  , [ "nucleus.num"                            ] ]
+      , "z_core"             : [ "float", [ "nucleus.num"                            ] ]
       , "local_n"            : [ "int"  , [ "nucleus.num"                            ] ]
       , "local_num_n_max"    : [ "int"  , [                                          ] ]
       , "local_exponent"     : [ "float", [ "nucleus.num", "ecp.local_num_n_max"     ] ]