For example, consider H2 with the following basis set (in GAMESS
format), where both the AOs and primitives are considered normalized:
@@ -905,33 +899,46 @@ P 1
P 1
1 3.880000E-01 1.000000E+00
D 1
-1 1.057000E+00 1.0000000
+1 1.057000E+00 1.000000E+00
-we have:
+In TREXIO representaion we have:
-type = "Gaussian"
-num = 12
-prim_num = 20
+type = "Gaussian"
+prim_num = 20
+shell_num = 12
-nucleus_index = [0 , 6]
-shell_ang_mom = [0 , 0 , 0 , 1 , 1 , 2 , 0 , 0 , 0 , 1 , 1 , 2 ]
-shell_prim_num = [5 , 1 , 1 , 1 , 1 , 1 , 5 , 1 , 1 , 1 , 1 , 1 ]
-shell_prim_index = [0 , 5 , 6 , 7 , 8 , 9 , 10, 15, 16, 17, 18, 19]
-shell_factor = [1., 1., 1., 1., 1., 1., 1., 1., 1., 1., 1., 1.]
+# 6 shells per H atom
+nucleus_index =
+[ 0, 0, 0, 0, 0, 0,
+ 1, 1, 1, 1, 1, 1 ]
+# 3 shells in S (l=0), 2 in P (l=1), 1 in D (l=2)
+ang_mom =
+[ 0, 0, 0, 1, 1, 2,
+ 0, 0, 0, 1, 1, 2 ]
+
+# no need to renormalize shells
+shell_factor =
+[ 1., 1., 1., 1., 1., 1.,
+ 1., 1., 1., 1., 1., 1. ]
+
+# 5 primitives for the first S shell and then 1 primitive per remaining shells in each H atom
+shell_index =
+[ 0, 0, 0, 0, 0, 1, 2, 3, 4, 5,
+ 6, 6, 6, 6, 6, 7, 8, 9, 10, 11 ]
+
+# parameters of the primitives (10 per H atom)
exponent =
-[ 33.87, 5.095, 1.159, 0.3258, 0.1027, 0.3258, 0.1027, 1.407,
- 0.388, 1.057, 33.87, 5.095, 1.159, 0.3258, 0.1027, 0.3258, 0.1027, 1.407,
- 0.388, 1.057]
+[ 33.87, 5.095, 1.159, 0.3258, 0.1027, 0.3258, 0.1027, 1.407, 0.388, 1.057,
+ 33.87, 5.095, 1.159, 0.3258, 0.1027, 0.3258, 0.1027, 1.407, 0.388, 1.057 ]
coefficient =
-[ 0.006068, 0.045308, 0.202822, 0.503903, 0.383421, 1.0, 1.0,
- 1.0, 1.0, 1.0, 0.006068, 0.045308, 0.202822, 0.503903, 0.383421, 1.0, 1.0,
- 1.0, 1.0, 1.0]
+[ 0.006068, 0.045308, 0.202822, 0.503903, 0.383421, 1.0, 1.0, 1.0, 1.0, 1.0,
+ 0.006068, 0.045308, 0.202822, 0.503903, 0.383421, 1.0, 1.0, 1.0, 1.0, 1.0 ]
prim_factor =
[ 1.0006253235944540e+01, 2.4169531573445120e+00, 7.9610924849766440e-01
@@ -944,9 +951,10 @@ prim_factor =