In this work, we generalize the recently proposed matrix product state perturbation theory (MPSPT) for calculating energies of excited states using quasi-degenerate (QD) perturbation theory. Our formulation uses the Kirtman-Certain-Hirschfelder canonical Van Vleck perturbation theory, which gives Hermitian effective Hamiltonians at each order, and also allows one to make use of Wigner’s 2n + 1 rule. Further, our formulation satisfies Granovsky’s requirement of model space invariance which is important for obtaining smooth potential energy curves. Thus, when we use MPSPT with the Dyall Hamiltonian, we obtain a model space invariant version of quasi-degenerate n-electron valence state perturbation theory (NEVPT), a property that the usual formulation of QD-NEVPT2 based on a multipartitioning technique lacked. We use our method on the benchmark problems of bond breaking of LiF which shows ionic to covalent curve crossing and the twist around the double bond of ethylene where significant valence-Rydberg mixing occurs in the excited states. In accordance with our previous work, we find that multi-reference linearized coupled cluster theory is more accurate than other multi-reference theories of similar cost.

1.
H.-J.
Werner
and
E.-A.
Reinsch
, “
The self-consistent electron pairs method for multiconfiguration reference state functions
,”
J. Chem. Phys.
76
(
6
),
3144
(
1982
).
2.
H.-J.
Werner
and
P. J.
Knowles
, “
An efficient internally contracted multiconfiguration-reference configuration interaction method
,”
J. Chem. Phys.
89
(
9
),
5803
(
1988
).
3.
S. R.
White
, “
Density matrix formulation for quantum renormalization groups
,”
Phys. Rev. Lett.
69
(
19
),
2863
(
1992
).
4.
S. R.
White
and
R. L.
Martin
, “
Ab initio quantum chemistry using the density matrix renormalization group
,”
J. Chem. Phys.
110
(
9
),
4127
(
1999
).
5.
S.
Wouters
,
W.
Poelmans
,
P. W.
Ayers
, and
D.
Van Neck
, “
CheMPS2: A free open-source spin-adapted implementation of the density matrix renormalization group for ab initio quantum chemistry
,”
Comput. Phys. Commun.
185
,
1501
1514
(
2014
).
6.
D.
Zgid
and
M.
Nooijen
, “
On the spin and symmetry adaptation of the density matrix renormalization group method
,”
J. Chem. Phys.
128
(
1
),
014107
(
2008
).
7.
G.
Moritz
,
B. A.
Hess
, and
M.
Reiher
, “
Convergence behavior of the density-matrix renormalization group algorithm for optimized orbital orderings
,”
J. Chem. Phys.
122
(
2
),
024107
(
2005
).
8.
Ö.
Legeza
and
J.
Sólyom
, “
Optimizing the density-matrix renormalization group method using quantum information entropy
,”
Phys. Rev. B
68
(
19
),
195116
(
2003
).
9.
Y.
Kurashige
and
T.
Yanai
, “
High-performance ab initio density matrix renormalization group method: Applicability to large-scale multireference problems for metal compounds
,”
J. Chem. Phys.
130
,
234114
(
2009
).
10.
G. K. L.
Chan
and
M.
Head-Gordon
, “
Highly correlated calculations with a polynomial cost algorithm: A study of the density matrix renormalization group
,”
J. Chem. Phys.
116
(
11
),
4462
(
2002
).
11.
G. H.
Booth
,
A. J. W.
Thom
, and
A.
Alavi
, “
Fermion Monte Carlo without fixed nodes: A game of life, death, and annihilation in Slater determinant space
,”
J. Chem. Phys.
131
(
5
),
054106
(
2009
).
12.
D.
Cleland
,
G. H.
Booth
, and
A.
Alavi
, “
Communications: Survival of the fittest: Accelerating convergence in full configuration-interaction quantum Monte Carlo
,”
J. Chem. Phys.
132
(
4
),
041103
(
2010
).
13.
F. R.
Petruzielo
,
A. A.
Holmes
,
H. J.
Changlani
,
M. P.
Nightingale
, and
C. J.
Umrigar
, “
Semistochastic projector Monte Carlo method
,”
Phys. Rev. Lett.
109
(
23
),
230201
(
2012
).
14.
G. H.
Booth
,
A.
Gruneis
,
G.
Kresse
, and
A.
Alavi
, “
Towards an exact description of electronic wavefunctions in real solids
,”
Nature
493
(
7432
),
365
370
(
2013
).
15.
Y.
Kurashige
and
T.
Yanai
, “
Second-order perturbation theory with a density matrix renormalization group self-consistent field reference function: Theory and application to the study of chromium dimer
,”
J. Chem. Phys.
135
(
9
),
094104
(
2011
).
16.
Y.
Kurashige
,
J.
Chalupský
,
T. N.
Lan
, and
T.
Yanai
, “
Complete active space second-order perturbation theory with cumulant approximation for extended active-space wavefunction from density matrix renormalization group
,”
J. Chem. Phys.
141
(
17
),
174111
(
2014
).
17.
R.
Kubo
, “
Generalized cumulant expansion method
,”
J. Phys. Soc. Jpn.
17
(
7
),
1100
1120
(
1962
).
18.
W.
Kutzelnigg
and
D.
Mukherjee
, “
Normal order and extended Wick theorem for a multiconfiguration reference wave function
,”
J. Chem. Phys.
107
(
2
),
432
(
1997
).
19.
D. A.
Mazziotti
, “
Anti-Hermitian contracted Schrödinger equation: Direct determination of the two-electron reduced density matrices of many-electron molecules
,”
Phys. Rev. Lett.
97
(
14
),
143002
(
2006
).
20.
T.
Yanai
,
Y.
Kurashige
,
E.
Neuscamman
, and
G. K.-L.
Chan
, “
Multireference quantum chemistry through a joint density matrix renormalization group and canonical transformation theory
,”
J. Chem. Phys.
132
(
2
),
024105
(
2010
).
21.
E.
Neuscamman
,
T.
Yanai
, and
G. K.-L.
Chan
, “
A review of canonical transformation theory
,”
Int. Rev. Phys. Chem.
29
(
2
),
231
(
2010
).
22.
M.
Saitow
,
Y.
Kurashige
, and
T.
Yanai
, “
Multireference configuration interaction theory using cumulant reconstruction with internal contraction of density matrix renormalization group wave function
,”
J. Chem. Phys.
139
(
4
),
044118
(
2013
).
23.
M.
Saitow
,
Y.
Kurashige
, and
T.
Yanai
, “
Fully internally contracted multireference configuration interaction theory using density matrix renormalization group: A reduced-scaling implementation derived by computer-aided tensor factorization
,”
J. Chem. Theory Comput.
11
,
5120
(
2015
).
24.
D.
Zgid
,
D.
Ghosh
,
E.
Neuscamman
, and
G. K.-L.
Chan
, “
A study of cumulant approximations to n-electron valence multireference perturbation theory
,”
J. Chem. Phys.
130
(
19
),
194107
(
2009
).
25.
S.
Sharma
and
G. K.-L.
Chan
, “
Communication: A flexible multi-reference perturbation theory by minimizing the Hylleraas functional with matrix product states
,”
J. Chem. Phys.
141
(
11
),
111101
(
2014
).
26.
S.
Sharma
and
A.
Alavi
, “
Multireference linearized coupled cluster theory for strongly correlated systems using matrix product states
,”
J. Chem. Phys.
143
(
10
),
102815
(
2015
).
27.
R. F.
Fink
, “
Two new unitary-invariant and size-consistent perturbation theoretical approaches to the electron correlation energy
,”
Chem. Phys. Lett.
428
(
4–6
),
461
466
(
2006
).
28.
R. F.
Fink
, “
The multi-reference retaining the excitation degree perturbation theory: A size-consistent, unitary invariant, and rapidly convergent wavefunction based ab initio approach
,”
Chem. Phys.
356
(
1–3
),
39
46
(
2009
).
29.
F.
Spiegelmann
and
J. P.
Malrieu
, “
The use of effective Hamiltonians for the treatment of avoided crossings. I. Adiabatic potential curves
,”
J. Phys. B: At. Mol. Phys.
17
(
7
),
1235
(
1984
).
30.
J.-P.
Malrieu
,
J.-L.
Heully
, and
A.
Zaitsevskii
, “
Multiconfigurational second-order perturbative methods: Overview and comparison of basic properties
,”
Theor. Chim. Acta
90
(
2–3
),
167
187
(
1995
).
31.
H.
Primas
, “
Generalized perturbation theory in operator form
,”
Rev. Mod. Phys.
35
(
3
),
710
711
(
1963
).
32.
B. H.
Brandow
, “
Linked-cluster expansions for the nuclear many-body problem
,”
Rev. Mod. Phys.
39
(
4
),
771
828
(
1967
).
33.
B.
Kirtman
, “
Variational form of Van Vleck degenerate perturbation theory with particular application to electronic structure problems
,”
J. Chem. Phys.
49
(
9
),
3890
(
1968
).
34.
P. R.
Certain
and
J. O.
Hirschfelder
, “
New partitioning perturbation theory. I. General formalism
,”
J. Chem. Phys.
52
(
12
),
5977
(
1970
).
35.
B.
Kirtman
, “
Simultaneous calculation of several interacting electronic states by generalized Van Vleck perturbation theory
,”
J. Chem. Phys.
75
(
2
),
798
(
1981
).
36.
I.
Shavitt
and
L. T.
Redmon
, “
Quasidegenerate perturbation theories. A canonical Van Vleck formalism and its relationship to other approaches
,”
J. Chem. Phys.
73
(
11
),
5711
(
1980
).
37.
U.
Schollwöck
, “
The density-matrix renormalization group in the age of matrix product states
,”
Ann. Phys.
326
(
1
),
96
(
2011
).
38.
G. K.-L.
Chan
and
S.
Sharma
, “
The density matrix renormalization group in quantum chemistry
,”
Annu. Rev. Phys. Chem.
62
(
1
),
465
(
2011
).
39.
C.
Angeli
,
R.
Cimiraglia
,
S.
Evangelisti
,
T.
Leininger
, and
J.-P.
Malrieu
, “
Introduction of n-electron valence states for multireference perturbation theory
,”
J. Chem. Phys.
114
(
23
),
10252
(
2001
).
40.
C.
Angeli
,
R.
Cimiraglia
, and
J.-P.
Malrieu
, “
n-electron valence state perturbation theory: A spinless formulation and an efficient implementation of the strongly contracted and of the partially contracted variants
,”
J. Chem. Phys.
117
(
20
),
9138
(
2002
).
41.
P.-O.
Lowdin
, “
Studies in perturbation theory. IV. Solution of eigenvalue problem by projection operator formalism
,”
J. Math. Phys.
3
(
5
),
969
(
1962
).
42.
H.
Nakano
, “
Quasidegenerate perturbation theory with multiconfigurational self-consistent-field reference functions
,”
J. Chem. Phys.
99
(
10
),
7983
(
1993
).
43.
H.
Nakano
,
R.
Uchiyama
, and
K.
Hirao
, “
Quasi-degenerate perturbation theory with general multiconfiguration self-consistent field reference functions
,”
J. Comput. Chem.
23
(
12
),
1166
1175
(
2002
).
44.
A. A.
Granovsky
, “
Extended multi-configuration quasi-degenerate perturbation theory: The new approach to multi-state multi-reference perturbation theory
,”
J. Chem. Phys.
134
(
21
),
214113
(
2011
).
45.
J.
Finley
,
P.-Å.
Malmqvist
,
B. O.
Roos
, and
L.
Serrano-Andrés
, “
The multi-state CASPT2 method
,”
Chem. Phys. Lett.
288
(
2–4
),
299
306
(
1998
).
46.
C.
Angeli
,
S.
Borini
,
M.
Cestari
, and
R.
Cimiraglia
, “
A quasidegenerate formulation of the second order n-electron valence state perturbation theory approach
,”
J. Chem. Phys.
121
(
9
),
4043
4049
(
2004
).
47.
A.
Zaitsevskii
and
J.-P.
Malrieu
, “
Multi-partitioning quasidegenerate perturbation theory. A new approach to multireference Møller-Plesset perturbation theory
,”
Chem. Phys. Lett.
233
(
5–6
),
597
604
(
1995
).
48.
T.
Shiozaki
,
W.
Gyorffy
,
P.
Celani
, and
H.-J.
Werner
, “
Communication: Extended multi-state complete active space second-order perturbation theory: Energy and nuclear gradients
,”
J. Chem. Phys.
135
(
8
),
081106
(
2011
).
49.
C. W.
Bauschlicher
and
S. R.
Langhoff
, “
Full configuration-interaction study of the ionicneutral curve crossing in LiF
,”
J. Chem. Phys.
89
(
7
),
4246
(
1988
).
50.
T. H.
Dunning
, “
Gaussian basis sets for use in correlated molecular calculations. I. The atoms boron through neon and hydrogen
,”
J. Chem. Phys.
90
(
2
),
1007
(
1989
).
51.
D. E.
Woon
and
T. H.
Dunning
, “
Gaussian basis sets for use in correlated molecular calculations. V. Core-valence basis sets for boron through neon
,”
J. Chem. Phys.
103
(
11
),
4572
(
1995
).
52.
S.
Sharma
and
G. K.-L.
Chan
, “
Spin-adapted density matrix renormalization group algorithms for quantum chemistry
,”
J. Chem. Phys.
136
(
12
),
124121
(
2012
).
53.
P. J.
Knowles
and
H.-J.
Werner
, “
Internally contracted multiconfiguration-reference configuration interaction calculations for excited states
,”
Theor. Chim. Acta
84
,
95
(
1992
).
54.
H.-J.
Werner
, “
Third-order multireference perturbation theory The CASPT3 method
,”
Mol. Phys.
89
(
2
),
645
661
(
1996
).
55.
H.-J.
Werner
,
P. J.
Knowles
,
G.
Knizia
,
F. R.
Manby
, and
M.
Schütz
, “
Molpro: A general-purpose quantum chemistry program package
,”
Wiley Interdiscip. Rev.: Comput. Mol. Sci.
2
(
2
),
242
253
(
2012
).
56.
M.
Barbatti
,
J.
Paier
, and
H.
Lischka
, “
Photochemistry of ethylene: {A} multireference configuration interaction investigation of the excited-state energy surfaces
,”
J. Chem. Phys.
121
(
23
),
11614
11624
(
2004
).
57.
M.
Ben-Nun
and
T. J.
Martnez
, “
Photodynamics of ethylene: Ab initio studies of conical intersections
,”
Chem. Phys.
259
(
23
),
237
248
(
2000
).
58.
R. P.
Krawczyk
,
A.
Viel
,
U.
Manthe
, and
W.
Domcke
, “
Photoinduced dynamics of the valence states of ethene: A six-dimensional potential-energy surface of three electronic states with several conical intersections
,”
J. Chem. Phys.
119
(
3
),
1397
1411
(
2003
).
59.
L. A.
Curtiss
,
K.
Raghavachari
,
P. C.
Redfern
, and
J. A.
Pople
, “
Assessment of Gaussian-2 and density functional theories for the computation of enthalpies of formation
,”
J. Chem. Phys.
106
(
3
),
1063
1079
(
1997
).
60.
P. C.
Hariharan
and
J. A.
Pople
, “
The influence of polarization functions on molecular orbital hydrogenation energies
,”
Theor. Chim. Acta
28
,
213
(
1973
).
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