diff --git a/adcc/backends/psi4.py b/adcc/backends/psi4.py
index 66ca8b38..69d97e6f 100644
--- a/adcc/backends/psi4.py
+++ b/adcc/backends/psi4.py
@@ -85,7 +85,6 @@ def correlated_gradient(self, g1_ao, w_ao, g2_ao_1, g2_ao_2):
             string = "TEI" + str(atom)
             deriv2 = self.mints.ao_tei_deriv1(atom)
             for p in range(3):
-                map_key = string + cart[p]
                 deriv2_np = np.asarray(deriv2[p])
                 Gradient["TEI"][atom, p] += np.einsum(
                     'pqrs,prqs->', g2_ao_1, deriv2_np, optimize=True
diff --git a/adcc/gradients/test_functionality_gradients.py b/adcc/gradients/test_functionality_gradients.py
new file mode 100644
index 00000000..80abe440
--- /dev/null
+++ b/adcc/gradients/test_functionality_gradients.py
@@ -0,0 +1,75 @@
+#!/usr/bin/env python3
+## vi: tabstop=4 shiftwidth=4 softtabstop=4 expandtab
+## ---------------------------------------------------------------------
+##
+## Copyright (C) 2020 by the adcc authors
+##
+## This file is part of adcc.
+##
+## adcc is free software: you can redistribute it and/or modify
+## it under the terms of the GNU General Public License as published
+## by the Free Software Foundation, either version 3 of the License, or
+## (at your option) any later version.
+##
+## adcc is distributed in the hope that it will be useful,
+## but WITHOUT ANY WARRANTY; without even the implied warranty of
+## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+## GNU General Public License for more details.
+##
+## You should have received a copy of the GNU General Public License
+## along with adcc. If not, see <http://www.gnu.org/licenses/>.
+##
+## ---------------------------------------------------------------------
+import unittest
+import itertools
+import adcc
+import adcc.backends
+
+from numpy.testing import assert_allclose
+
+import pytest
+
+from ..misc import expand_test_templates
+from adcc.backends.testing import cached_backend_hf
+from adcc.testdata.cache import gradient_data
+
+
+backends = [b for b in adcc.backends.available()
+            if b not in ["molsturm", "veloxchem"]]
+molecules = ["h2o"]
+basissets = ["sto3g", "ccpvdz"]
+methods = ["mp2", "adc1", "adc2"]
+combinations = list(itertools.product(molecules, basissets, methods, backends))
+
+
+@pytest.mark.skipif(len(backends) == 0, reason="No backend found.")
+@expand_test_templates(combinations)
+class TestNuclearGradients(unittest.TestCase):
+    def template_nuclear_gradient(self, molecule, basis, method, backend):
+        grad_ref = gradient_data[molecule][basis][method]
+
+        energy_ref = grad_ref["energy"]
+        grad_fdiff = grad_ref["gradient"]
+
+        scfres = cached_backend_hf(backend, molecule, basis, conv_tol=1e-13)
+        if "adc" in method:
+            # TODO: convergence needs to be very very tight...
+            # so we want to make sure all vectors are tightly converged
+            n_limit = 5
+            state = adcc.run_adc(scfres, method=method,
+                                 n_singlets=10, conv_tol=1e-11)
+            for ee in state.excitations[:n_limit]:
+                grad = adcc.nuclear_gradient(ee)
+                assert_allclose(energy_ref[ee.index], ee.total_energy, atol=1e-10)
+                assert_allclose(
+                    grad_fdiff[ee.index], grad["Total"], atol=1e-7
+                )
+        else:
+            # MP2 gradients
+            refstate = adcc.ReferenceState(scfres)
+            mp = adcc.LazyMp(refstate)
+            grad = adcc.nuclear_gradient(mp)
+            assert_allclose(energy_ref, mp.energy(2), atol=1e-8)
+            assert_allclose(
+                grad_fdiff, grad["Total"], atol=1e-8
+            )
diff --git a/adcc/testdata/cache.py b/adcc/testdata/cache.py
index 4dbfab89..7f6517f8 100644
--- a/adcc/testdata/cache.py
+++ b/adcc/testdata/cache.py
@@ -258,3 +258,4 @@ def read_yaml_data(fname):
 
 qchem_data = read_yaml_data("qchem_dump.yml")
 tmole_data = read_yaml_data("tmole_dump.yml")
+gradient_data = read_yaml_data("grad_dump.yml")
diff --git a/adcc/testdata/dump_fdiff_gradient.py b/adcc/testdata/dump_fdiff_gradient.py
new file mode 100644
index 00000000..16da630e
--- /dev/null
+++ b/adcc/testdata/dump_fdiff_gradient.py
@@ -0,0 +1,139 @@
+#!/usr/bin/env python3
+## vi: tabstop=4 shiftwidth=4 softtabstop=4 expandtab
+## ---------------------------------------------------------------------
+##
+## Copyright (C) 2021 by the adcc authors
+##
+## This file is part of adcc.
+##
+## adcc is free software: you can redistribute it and/or modify
+## it under the terms of the GNU General Public License as published
+## by the Free Software Foundation, either version 3 of the License, or
+## (at your option) any later version.
+##
+## adcc is distributed in the hope that it will be useful,
+## but WITHOUT ANY WARRANTY; without even the implied warranty of
+## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+## GNU General Public License for more details.
+##
+## You should have received a copy of the GNU General Public License
+## along with adcc. If not, see <http://www.gnu.org/licenses/>.
+##
+## ---------------------------------------------------------------------
+import itertools
+import adcc
+import numpy as np
+import yaml
+from tqdm import tqdm
+
+from pyscf import gto
+
+from static_data import xyz
+
+
+prefactors_5p = np.array([1.0, -8.0, 8.0, -1.0]) / 12.0
+multipliers_5p = [-2, -1, 1, 2]
+coords_label = ["x", "y", "z"]
+
+
+def _molstring(elems, coords):
+    s = ""
+    for kk, (i, c) in enumerate(zip(elems, coords)):
+        s += f"{i} {c[0]} {c[1]} {c[2]}"
+        if kk != len(elems) - 1:
+            s += "\n"
+    return s
+
+
+def adc_energy(scfres, method, **kwargs):
+    state = adcc.run_adc(method=method, data_or_matrix=scfres,
+                         output=None, **kwargs)
+    return state.total_energy
+
+
+def mp_energy(scfres, method, **kwargs):
+    level = {
+        "mp2": 2,
+        "mp3": 3,
+    }
+    refstate = adcc.ReferenceState(scfres)
+    return adcc.LazyMp(refstate).energy(level[method])
+
+
+def fdiff_gradient(molstring, method, basis, step=1e-4, **kwargs):
+    m = gto.M(atom=molstring, unit='Bohr', basis=basis)
+    coords = m.atom_coords().copy()
+    elements = m.elements.copy()
+
+    n_grads = kwargs.get("n_singlets", 1)
+    conv_tol = kwargs.get("conv_tol", 1e-10) / 10
+
+    # run unperturbed system
+    scfres = adcc.backends.run_hf(
+        'pyscf', molstring, basis, conv_tol=conv_tol, conv_tol_grad=conv_tol
+    )
+    if "adc" in method:
+        en = adc_energy(scfres, method, **kwargs)
+    else:
+        en = mp_energy(scfres, method, **kwargs)
+
+    natoms = len(elements)
+    grad = np.zeros((n_grads, natoms, 3))
+    at_c = list(itertools.product(range(natoms), range(3)))
+    for i, c in tqdm(at_c):
+        for f, p in zip(multipliers_5p, prefactors_5p):
+            coords_p = coords.copy()
+            coords_p[i, c] += f * step
+            geom_p = _molstring(elements, coords_p)
+            scfres = adcc.backends.run_hf(
+                'pyscf', geom_p, basis, conv_tol=conv_tol, conv_tol_grad=conv_tol
+            )
+            if "adc" in method:
+                en_pert = adc_energy(scfres, method, **kwargs)
+            else:
+                en_pert = mp_energy(scfres, method, **kwargs)
+            grad[:, i, c] += p * en_pert / step
+    return en, grad
+
+
+def main():
+    config_excited = {
+        "n_singlets": 5,
+    }
+    basissets = [
+        "sto3g",
+        "ccpvdz",
+    ]
+    methods = [
+        "mp2",
+        "adc1",
+        "adc2",
+    ]
+    molecules = ["h2o", "hf", "formaldehyde"]
+    ret = {}
+    for molecule in molecules:
+        ret[molecule] = {}
+        for basis in basissets:
+            ret[molecule][basis] = {}
+            for method in methods:
+                kwargs = {
+                    "conv_tol": 1e-8,
+                }
+                if "adc" in method:
+                    kwargs.update(config_excited)
+                basename = f"{molecule}_{basis}_{method}"
+                print(f"Evaluating finite difference gradient for {basename}.")
+                en, grad = fdiff_gradient(xyz[molecule], method, basis, **kwargs)
+                if isinstance(en, np.ndarray):
+                    en = en.tolist()
+                cont = {
+                    "energy": en,
+                    "gradient": np.squeeze(grad).tolist(),
+                }
+                ret[molecule][basis][method] = cont
+    with open("grad_dump.yml", "w") as yamlout:
+        yaml.safe_dump(ret, yamlout)
+
+
+if __name__ == "__main__":
+    main()
diff --git a/adcc/testdata/grad_dump.yml b/adcc/testdata/grad_dump.yml
new file mode 100644
index 00000000..f24064ae
--- /dev/null
+++ b/adcc/testdata/grad_dump.yml
@@ -0,0 +1,717 @@
+formaldehyde:
+  ccpvdz:
+    adc1:
+      energy:
+      - -113.70558203635709
+      - -113.50558431199366
+      - -113.49341052539295
+      - -113.4921906128972
+      - -113.43838517589901
+      gradient:
+      - - - 0.004440058954060078
+          - -0.08440320886438712
+          - 0.061171111461590044
+        - - -0.0046579049521824345
+          - 0.08556581632001325
+          - -0.06425038322049659
+        - - -0.00018499072757549584
+          - -0.003402824906515889
+          - -0.002396157040493563
+        - - 0.00040283604175783694
+          - 0.002240217392682098
+          - 0.0054754264710936695
+      - - - 0.014108372910413891
+          - -0.26049620006233454
+          - 0.19367707810306456
+        - - -0.012959809566382319
+          - 0.2366245447192341
+          - -0.17844389395031612
+        - - -0.0014201861922629178
+          - 0.0031937859166646376
+          - -0.018929093901533633
+        - - 0.0002716220624279231
+          - 0.020677869601058774
+          - 0.003695907857036218
+      - - - 0.01106323792191688
+          - -0.20612725264800247
+          - 0.1539881363278255
+        - - -0.012415087621775456
+          - 0.22842276237497572
+          - -0.17184760025702417
+        - - 4.062271909788251e-05
+          - -0.018368309567449614
+          - 0.00045038078678771853
+        - - 0.0013112259184708819
+          - -0.003927204335923307
+          - 0.017409080843208358
+      - - - -0.007417373723001219
+          - 0.13012286479352042
+          - -0.10184336615202483
+        - - 0.004234577005263418
+          - -0.07607176668534521
+          - 0.05810191675845999
+        - - -0.001716892686090432
+          - -0.0594009895430645
+          - -0.02237362222513184
+        - - 0.004899689141893759
+          - 0.005349896222469397
+          - 0.06611506904300768
+      - - - 0.003353650274220854
+          - -0.0640643189108232
+          - 0.04545981872070115
+        - - -0.009704219817649573
+          - 0.1790985528350575
+          - -0.13405693606182467
+        - - 0.001255770490388386
+          - -0.07730495402938686
+          - 0.018640203212271444
+        - - 0.005094795822515152
+          - -0.037729280651547015
+          - 0.0699569108983269
+    adc2:
+      energy:
+      - -114.04108709429852
+      - -113.90116030505898
+      - -113.84093754181639
+      - -113.83275876700296
+      - -113.78729359707486
+      gradient:
+      - - - 0.00795411376748234
+          - -0.14761182830261532
+          - 0.10940460005076602
+        - - -0.00861854647519067
+          - 0.15725425074924715
+          - -0.11885035762679763
+        - - -0.00038722751196473837
+          - -0.011867678796988912
+          - -0.004902817323454656
+        - - 0.0010516593320062384
+          - 0.002225256263045594
+          - 0.014348573065944947
+      - - - 0.0022481144114863127
+          - -0.04510061517066788
+          - 0.03181697831314523
+        - - -0.0042847725708270445
+          - 0.07931772326992359
+          - -0.059501681782421656
+        - - -0.002496956309187226
+          - -0.05234425392700359
+          - -0.03315452564856969
+        - - 0.004533617960987613
+          - 0.01812714702100493
+          - 0.060839227138785645
+      - - - 0.012822667238651775
+          - -0.23806948866695166
+          - 0.17628057644469664
+        - - -0.012922618945594877
+          - 0.23657256651495118
+          - -0.17811991584312636
+        - - -0.0011136162065668032
+          - -0.011240343621466309
+          - -0.014638555672718212
+        - - 0.001213567695231177
+          - 0.01273726558429189
+          - 0.016477893106639385
+      - - - 0.006636413134401664
+          - -0.12150684717926197
+          - 0.09214128745952621
+        - - -0.007791586889652535
+          - 0.13977801451983396
+          - -0.10773590055759996
+        - - -0.0020652523526223376
+          - -0.03424370722495951
+          - -0.02755755910766311
+        - - 0.0032204291637754068
+          - 0.015972540670190938
+          - 0.04315217011026107
+      - - - 0.013698791502974927
+          - -0.251412856116076
+          - 0.1891322702722391
+        - - -0.014349782286444679
+          - 0.26074345722736325
+          - -0.1981027886213269
+        - - -0.0005066021985840052
+          - -0.012612845370313153
+          - -0.006683660205453634
+        - - 0.0011628166976151988
+          - 0.0032822444336488843
+          - 0.01565417618257925
+    mp2:
+      energy: -114.19562447602232
+      gradient:
+      - - 0.0006307709263637662
+        - -0.019193962754798122
+        - 0.009753386213560589
+      - - -0.0019824629416689277
+        - 0.039011894245049916
+        - -0.027773341484135017
+      - - -0.00016380085435230285
+        - -0.018570978703792207
+        - -0.0022151207958813757
+      - - 0.001515490803285502
+        - -0.0012469533103285357
+        - 0.020235072865034454
+  sto3g:
+    adc1:
+      energy:
+      - -112.35215847657514
+      - -112.19031679061341
+      - -111.99509653412369
+      - -111.88323868990281
+      - -111.83938478075873
+      gradient:
+      - - - 134.86789705506817
+          - -0.034582075124490075
+          - 0.020427761948667467
+        - - 134.86667057021987
+          - 0.052714954770635813
+          - -0.03787164441018831
+        - - 0.00025331013603135943
+          - -0.01337217444961425
+          - 0.0032829746487550437
+        - - 0.0010667957249097526
+          - -0.004760705487569794
+          - 0.014160908656776883
+      - - - 297.5504788887192
+          - -0.034582075124490075
+          - 0.02042776206508279
+        - - 297.55109127634205
+          - -1078.7981471754028
+          - -0.03787164441018831
+        - - 0.00025331013603135943
+          - -0.01337217444961425
+          - 0.0032829746487550437
+        - - 0.0010667956084944308
+          - -0.004760705487569794
+          - 0.014160908656776883
+      - - - 390.76501749145973
+          - -0.034582075124490075
+          - 0.020427761948667467
+        - - 390.7668319265358
+          - -2380.202243736072
+          - -0.03787164441018831
+        - - 0.00025331013603135943
+          - -0.01337217444961425
+          - 0.0032829746342031285
+        - - 0.0010667956084944308
+          - -0.004760705487569794
+          - 0.014160908889607526
+      - - - -786.4960951929388
+          - -0.20038470218423754
+          - 0.14833348176034633
+        - - 292.43344181386055
+          - -2046.8663960878475
+          - -0.1458953901892528
+        - - 0.00011068112507928163
+          - 0.005674898813595064
+          - 0.0014126732130534947
+        - - -0.0002842362300725654
+          - 0.0014252170512918383
+          - -0.003850776600302197
+      - - - -2099.6204833368683
+          - -0.3076474006084027
+          - 0.22782272301265039
+        - - 280.7667978423997
+          - -1037.8032912445778
+          - -0.21819978098210413
+        - - -0.0010586392600089312
+          - 0.0016113087913254276
+          - -0.01425015923450701
+        - - 0.00035280417068861425
+          - 0.016332442552084103
+          - 0.004627213449566625
+    adc2:
+      energy:
+      - -112.29308371327538
+      - -112.08687577389874
+      - -111.95501913710211
+      - -111.94227341486139
+      - -111.90760777025828
+      gradient:
+      - - - 0.013361435267142951
+          - -0.24680471101601142
+          - 0.1840638013818534
+        - - -0.014295267901616171
+          - 0.26064838070305996
+          - -0.19721643527736887
+        - - -0.0002812701713992283
+          - -0.014264499128330499
+          - -0.003434756348724477
+        - - 0.0012151370465289801
+          - 0.0004208378813927993
+          - 0.016587377016549
+      - - - 0.014545091849868186
+          - -0.27108486875658855
+          - 0.20018935947155114
+        - - -0.015414420442539267
+          - 0.2825872143293964
+          - -0.2125983986479696
+        - - -0.001122399786254391
+          - -0.021760659903520718
+          - -0.014614149200497195
+        - - 0.0019917527242796496
+          - 0.010258322567096911
+          - 0.02702318166848272
+      - - - 0.015574866061797366
+          - -0.2841585915739415
+          - 0.21446659980574623
+        - - -0.020418328887899406
+          - 0.3722419853147585
+          - -0.2819262643606635
+        - - -0.0001184115099022165
+          - -0.06981211320089642
+          - -0.00022668807650916278
+        - - 0.004961850616382435
+          - -0.018271274529979564
+          - 0.06768634595209733
+      - - - 0.008447872693068348
+          - -0.15336673270212486
+          - 0.11524418441695161
+        - - -0.016566408987273462
+          - 0.30309375702927355
+          - -0.2287056674977066
+        - - 0.0015225222159642726
+          - -0.10094543961167801
+          - 0.022824064188171178
+        - - 0.006595998158445582
+          - -0.04878158635983709
+          - 0.0906374234764371
+      - - - 0.00431169880903326
+          - -0.08202417510619853
+          - 0.0608073133189464
+        - - -0.013763464201474562
+          - 0.25251537734584417
+          - -0.19093284106929787
+        - - -0.013066680257907137
+          - -0.26406628522090614
+          - -0.17279423588479403
+        - - 0.0225185089657316
+          - 0.09357509708206635
+          - 0.3029197411815403
+    mp2:
+      energy: -112.46495424382846
+      gradient:
+      - - 0.0037697695079259574
+        - -0.07685817136371043
+        - 0.05298948941344861
+      - - -0.006090689610573463
+        - 0.11399357361369766
+        - -0.08449994814873207
+      - - -2.156686969101429e-05
+        - -0.030690345840412192
+        - -4.766431811731309e-05
+      - - 0.0023424898099619895
+        - -0.0064450563077116385
+        - 0.03155812271870673
+h2o:
+  ccpvdz:
+    adc1:
+      energy:
+      - -75.68543998424987
+      - -75.61931016166072
+      - -75.59868950195046
+      - -75.53275298660013
+      - -75.45558187453754
+      gradient:
+      - - - 0.0927401026856387
+          - -7.275957614183426e-12
+          - 0.06558009374566609
+        - - -0.002630199545819778
+          - 7.275957614183426e-12
+          - -0.09467175448662601
+        - - -0.090109874116024
+          - -7.275957614183426e-12
+          - 0.029091669573972467
+      - - - 0.10931799972604495
+          - -7.275957614183426e-12
+          - 0.07809552933758823
+        - - -0.006660687533440068
+          - -7.275957614183426e-12
+          - -0.10735300042870222
+        - - -0.10265728522063
+          - -2.1827872842550278e-11
+          - 0.029257479851366952
+      - - - 0.011670212486933451
+          - 1.4551915228366852e-11
+          - 0.0084512654793798
+        - - 0.0568447552213911
+          - -7.275957614183426e-12
+          - -0.09296223078126786
+        - - -0.06851510248088744
+          - 7.275957614183426e-12
+          - 0.08451095721829915
+      - - - 0.02628810688474914
+          - 2.1827872842550278e-11
+          - 0.0192561547155492
+        - - 0.05759759972715983
+          - -1.4551915228366852e-11
+          - -0.11000343628256815
+        - - -0.08388586723594926
+          - 1.4551915228366852e-11
+          - 0.09074727105326019
+      - - - 0.28210171702085063
+          - 0.0
+          - 0.19977481755631743
+        - - -0.0784058679928421
+          - 2.1827872842550278e-11
+          - -0.1887100828025723
+        - - -0.20369583381398115
+          - 1.4551915228366852e-11
+          - -0.011064729405916296
+    adc2:
+      energy:
+      - -75.9296754081454
+      - -75.85499790104548
+      - -75.84309170282057
+      - -75.76675240722146
+      - -75.66953798873493
+      gradient:
+      - - - 0.11448502987332176
+          - -7.275957614183426e-12
+          - 0.08113865628547501
+        - - -0.008900619628548156
+          - -5.093170329928398e-11
+          - -0.10905678830749821
+        - - -0.1055843778376584
+          - 2.1827872842550278e-11
+          - 0.027918141058762558
+      - - - 0.11318147835117998
+          - -7.275957614183426e-12
+          - 0.0806558419499197
+        - - -0.0044726167325279675
+          - -1.4551915228366852e-11
+          - -0.11437428160570562
+        - - -0.10870887277997099
+          - 7.275957614183426e-12
+          - 0.033718444654368795
+      - - - 0.02205561503797071
+          - 0.0
+          - 0.015903162260656245
+        - - 0.05098408467893023
+          - 1.4551915228366852e-11
+          - -0.09580103932239581
+        - - -0.07303977520496119
+          - 7.275957614183426e-12
+          - 0.07989787455153419
+      - - - 0.020305528247263283
+          - 0.0
+          - 0.014960411695938092
+        - - 0.05805036811216269
+          - -1.4551915228366852e-11
+          - -0.10423131706920685
+        - - -0.07835603128478397
+          - 7.275957614183426e-12
+          - 0.08927089755161433
+      - - - 0.26928592537296936
+          - 2.1827872842550278e-11
+          - 0.19073858212505002
+        - - -0.07746150083403336
+          - 2.1827872842550278e-11
+          - -0.17647508150548674
+        - - -0.1918244067055639
+          - -2.1827872842550278e-11
+          - -0.014263495162595063
+    mp2:
+      energy: -76.22940338787204
+      gradient:
+      - - 0.02439544230583124
+        - -2.9103830456733704e-11
+        - 0.017738174385158345
+      - - -0.010762452344351914
+        - 1.4551915228366852e-11
+        - -0.011150372949487064
+      - - -0.013632995360239875
+        - -7.275957614183426e-12
+        - -0.006587801886780653
+  sto3g:
+    adc1:
+      energy:
+      - -74.47588319597438
+      - -74.38511885048017
+      - -74.3571822920925
+      - -74.2490420036088
+      - -74.13327522706486
+      gradient:
+      - - - 0.2519565806724131
+          - -1.4551915228366852e-11
+          - 0.17643764430249576
+        - - 0.04383796844922472
+          - 1.4551915228366852e-11
+          - -0.32756816375331255
+        - - -0.2957945393209229
+          - -2.1827872842550278e-11
+          - 0.15113050528452732
+      - - - 0.4420401885145111
+          - -2.9103830456733704e-11
+          - 0.31597313308157027
+        - - -0.08205663535773056
+          - -7.275957614183426e-12
+          - -0.35633137811964843
+        - - -0.35998354491312057
+          - 2.1827872842550278e-11
+          - 0.04035823367303237
+      - - - 0.10246271751384484
+          - -2.1827872842550278e-11
+          - 0.07140889731817879
+        - - 0.11964530679688323
+          - -1.4551915228366852e-11
+          - -0.2768456041376339
+        - - -0.22210801561595872
+          - 7.275957614183426e-12
+          - 0.20543669633480022
+      - - - 0.3338767071109032
+          - 1.4551915228366852e-11
+          - 0.23875348844012478
+        - - -2.251137630082667e-05
+          - 0.0
+          - -0.3568454495543847
+        - - -0.33385419509431813
+          - -2.9103830456733704e-11
+          - 0.11809195824025664
+      - - - 0.42701523288997123
+          - 0.0
+          - 0.30206555198674323
+        - - -0.0510407709152787
+          - -7.275957614183426e-12
+          - -0.3809664128420991
+        - - -0.37597446207655594
+          - 0.0
+          - 0.07890085934195668
+    adc2:
+      energy:
+      - -74.52306494758602
+      - -74.42102314285322
+      - -74.39990473420288
+      - -74.28060927293537
+      - -74.15388076828575
+      gradient:
+      - - - 0.27296631058561616
+          - 2.9103830456733704e-11
+          - 0.19153598658158444
+        - - 0.04375171761785168
+          - 2.9103830456733704e-11
+          - -0.3499776713724714
+        - - -0.3167180179952993
+          - 7.275957614183426e-12
+          - 0.15844167019531596
+      - - - 0.46611143292102497
+          - -7.275957614183426e-12
+          - 0.332718367826601
+        - - -0.08526563550549326
+          - 7.275957614183426e-12
+          - -0.377055163771729
+        - - -0.3808457903069211
+          - -1.6007106751203537e-10
+          - 0.04433678551140474
+      - - - 0.1245402002314222
+          - 1.4551915228366852e-11
+          - 0.08709251808613772
+        - - 0.11524764178466285
+          - -1.4551915228366852e-11
+          - -0.29412154671445023
+        - - -0.23978783340135124
+          - 7.275957614183426e-12
+          - 0.20702901783079142
+      - - - 0.344924942983198
+          - -2.1827872842550278e-11
+          - 0.2464642068516696
+        - - -0.001407823758199811
+          - 0.0
+          - -0.3665060569619527
+        - - -0.34351711843919475
+          - 2.1827872842550278e-11
+          - 0.1200418468870339
+      - - - 0.43142601163708605
+          - 2.1827872842550278e-11
+          - 0.3051797001535306
+        - - -0.050288449914660305
+          - -1.4551915228366852e-11
+          - -0.38670489951618947
+        - - -0.38113756212987937
+          - 7.275957614183426e-12
+          - 0.08152519822033355
+    mp2:
+      energy: -74.99357808910268
+      gradient:
+      - - 0.09648089321126463
+        - -2.1827872842550278e-11
+        - 0.0688644905021647
+      - - -0.026183462534390856
+        - -7.275957614183426e-12
+        - -0.06597386132489191
+      - - -0.07029743238672381
+        - 7.275957614183426e-12
+        - -0.002890627903980203
+hf:
+  ccpvdz:
+    adc1:
+      energy:
+      - -99.68449862868913
+      - -99.68449862864962
+      - -99.50075872824259
+      - -99.05905941167467
+      - -99.05905941155399
+      gradient:
+      - - - 4.3655745685100555e-11
+          - -4.3655745685100555e-11
+          - 0.05474575013795402
+        - - 1.4551915228366852e-11
+          - 1.4551915228366852e-11
+          - -0.05474577005952597
+      - - - 5.820766091346741e-11
+          - -4.3655745685100555e-11
+          - 0.05474574991967529
+        - - 1.4551915228366852e-11
+          - 2.9103830456733704e-11
+          - -0.054745770030422136
+      - - - -4.3655745685100555e-11
+          - 4.3655745685100555e-11
+          - 0.029345564864343032
+        - - -4.3655745685100555e-11
+          - 0.0
+          - -0.029341923116589896
+      - - - 7.275957614183426e-11
+          - -4.3655745685100555e-11
+          - -0.1574882440181682
+        - - 2.9103830456733704e-11
+          - 0.0
+          - 0.15748825178889092
+      - - - -5.820766091346741e-11
+          - -4.3655745685100555e-11
+          - -0.1574882423155941
+        - - 4.3655745685100555e-11
+          - 1.4551915228366852e-11
+          - 0.15748825231275987
+    adc2:
+      energy:
+      - -99.94395193294302
+      - -99.9439519329312
+      - -99.73699393315073
+      - -99.43877070940161
+      - -99.43877070915488
+      gradient:
+      - - - 0.0
+          - 5.820766091346741e-11
+          - 0.07390241048415191
+        - - 1.4551915228366852e-11
+          - 0.0
+          - -0.07390240793756675
+      - - - -5.820766091346741e-11
+          - 0.0
+          - 0.07390241093526129
+        - - -2.9103830456733704e-11
+          - -4.3655745685100555e-11
+          - -0.07390240782115143
+      - - - -1.3096723705530167e-10
+          - 5.820766091346741e-11
+          - 0.04055179744318593
+        - - -2.9103830456733704e-11
+          - -4.3655745685100555e-11
+          - -0.04055119516851846
+      - - - 2.9103830456733704e-11
+          - -4.3655745685100555e-11
+          - -0.006900888605741784
+        - - -4.3655745685100555e-11
+          - 0.0
+          - 0.00690086766553577
+      - - - -1.4551915228366852e-11
+          - 4.3655745685100555e-11
+          - -0.006900887412484735
+        - - -8.731149137020111e-11
+          - -1.4551915228366852e-11
+          - 0.0069008679274702445
+    mp2:
+      energy: -100.14365279000066
+      gradient:
+      - - 2.9103830456733704e-11
+        - -4.3655745685100555e-11
+        - -0.13385940197622404
+      - - -2.9103830456733704e-11
+        - 2.9103830456733704e-11
+        - 0.13385939724685159
+  sto3g:
+    adc1:
+      energy:
+      - -98.26160079719433
+      - -98.26160079719432
+      - -97.86355144712479
+      - -97.20550168819246
+      - -73.02590622379267
+      gradient:
+      - - - -5.820766091346741e-11
+          - 0.0
+          - 0.0459835930087138
+        - - 2.9103830456733704e-11
+          - -2.9103830456733704e-11
+          - -0.04598359337251168
+      - - - -5.820766091346741e-11
+          - 0.0
+          - 0.0459835930087138
+        - - 0.0
+          - -2.9103830456733704e-11
+          - -0.04598359337251168
+      - - - -2.9103830456733704e-11
+          - 0.0
+          - 0.05563517109840177
+        - - -2.9103830456733704e-11
+          - -4.3655745685100555e-11
+          - -0.055635170749155805
+      - - - 2.9103830456733704e-11
+          - -4.3655745685100555e-11
+          - 0.07153463260328863
+        - - -1.4551915228366852e-11
+          - -4.3655745685100555e-11
+          - -0.07153463290887885
+      - - - 1.4551915228366852e-11
+          - -7.275957614183426e-12
+          - 0.009702209834358655
+        - - 1.4551915228366852e-11
+          - -1.4551915228366852e-11
+          - -0.00970221107127145
+    adc2:
+      energy:
+      - -98.30973760269728
+      - -98.30973760269728
+      - -97.88705005686671
+      - -97.31155583033184
+      - -96.96183479769606
+      gradient:
+      - - - 1.1641532182693481e-10
+          - -4.3655745685100555e-11
+          - 0.08218655599921476
+        - - 7.275957614183426e-11
+          - 2.9103830456733704e-11
+          - -0.08218655640666839
+      - - - 0.0
+          - 7.275957614183426e-11
+          - 0.08218655599921476
+        - - -4.3655745685100555e-11
+          - 1.4551915228366852e-10
+          - -0.08218655629025307
+      - - - -1.1641532182693481e-10
+          - 2.9103830456733704e-11
+          - 0.04958453155995812
+        - - 0.0
+          - -2.9103830456733704e-11
+          - -0.04958453113795258
+      - - - 0.0
+          - 5.820766091346741e-11
+          - 0.15719162416644394
+        - - -1.4551915228366852e-11
+          - -5.820766091346741e-11
+          - -0.15719162434106693
+      - - - -2.9103830456733704e-11
+          - -1.7462298274040222e-10
+          - 0.4785101861489238
+        - - 2.9103830456733704e-11
+          - -5.820766091346741e-11
+          - -0.47851018683286384
+    mp2:
+      energy: -98.52261046811574
+      gradient:
+      - - 0.0
+        - 1.4551915228366852e-11
+        - -0.14964825809875038
+      - - 0.0
+        - 0.0
+        - 0.14964825844799634