A scheme for the calculation of molecular properties within the framework of unitary coupled-cluster (UCC) theory in both the electronic ground and excited states is presented. The scheme is based on an expectation-value ansatz, similar to the equation-of-motion coupled-cluster method or the intermediate state representation (ISR) approach of the algebraic–diagrammatic construction (ADC) scheme. Due to the UCC ansatz, the resulting equations cannot be given by closed-form expressions but need to be approximated. Explicit expressions for the expectation value of a general one-particle operator correct through second order in perturbation theory have been derived and coded for the electronic ground state as well as for excited states of predominant single-excitation character. The resulting equations are shown to be equivalent to those of the second-order ADC/ISR procedure. As first computational tests, the second-order UCC method (UCC2) and the one employing third-order amplitudes (also eigenvectors) together with the second-order density matrix, denoted as UCC3(2), are applied to the calculation of dipole moments for a series of small closed- and open-shell systems as well as 4-cyanoindole and 2,3-benzofuran and compared to full configuration interaction or experimental results. For the aromatic organic molecules, the UCC2 method is shown to be sufficient for the ground-state dipole moment, whereas the UCC3(2) scheme is superior for excited-state dipole moments.

1.
R.
McWeeny
,
Methods of Molecular Quantum Mechanics
, Theoretical Chemistry, 2nd ed. (
Academic Press
,
London
,
1992
).
2.
Methods in Computational Molecular Physics
, edited by
S.
Wilson
and
G. H. F.
Diercksen
(
Springer US
,
Boston, MA
,
1992
).
3.
F.
Neese
,
Coord. Chem. Rev.
253
,
526
(
2009
).
4.
T.
Helgaker
,
S.
Coriani
,
P.
Jørgensen
,
K.
Kristensen
,
J.
Olsen
, and
K.
Ruud
,
Chem. Rev.
112
,
543
(
2012
).
5.
H.
Hellmann
,
Einführung in die Quantenchemie
(
Deuticke
,
Leipzig
,
1937
).
6.
R. P.
Feynman
,
Phys. Rev.
56
,
340
(
1939
).
7.
G. W.
Trucks
,
E. A.
Salter
,
C.
Sosa
, and
R. J.
Bartlett
,
Chem. Phys. Lett.
147
,
359
(
1988
).
8.
M.
Hodecker
,
D. R.
Rehn
,
A.
Dreuw
, and
S.
Höfener
,
J. Chem. Phys.
150
,
164125
(
2019
).
9.
M.
Hodecker
, “
Development and application of Hermitian methods for molecular properties and excited electronic states
,” Ph.D. thesis,
Universität Heidelberg
,
2020
.
11.
A.
Heßelmann
and
A.
Görling
,
Mol. Phys.
109
,
2473
(
2011
).
12.
H.
Eshuis
,
J. E.
Bates
, and
F.
Furche
,
Theor. Chem. Acc.
131
,
1084
(
2012
).
13.
E. S.
Nielsen
,
P.
Jørgensen
, and
J.
Oddershede
,
J. Chem. Phys.
73
,
6238
(
1980
).
14.
J.
Oddershede
,
Adv. Chem. Phys.
69
,
201
(
1987
).
15.
K. L.
Bak
,
H.
Koch
,
J.
Oddershede
,
O.
Christiansen
, and
S. P. A.
Sauer
,
J. Chem. Phys.
112
,
4173
(
2000
).
16.
J.
Schirmer
,
Phys. Rev. A
26
,
2395
(
1982
).
17.
A. B.
Trofimov
,
G.
Stelter
, and
J.
Schirmer
,
J. Chem. Phys.
111
,
9982
(
1999
).
18.
A.
Dreuw
and
M.
Wormit
,
Wiley Interdiscip. Rev.: Comput. Mol. Sci.
5
,
82
(
2015
).
19.
J.
Schirmer
,
Many-Body Methods for Atoms, Molecules and Clusters
(
Springer International Publishing
,
2018
).
21.
J.
Schirmer
and
A. B.
Trofimov
,
J. Chem. Phys.
120
,
11449
(
2004
).
22.
R. J.
Bartlett
,
Annu. Rev. Phys. Chem.
32
,
359
(
1981
).
23.
T. D.
Crawford
and
H. F.
Schaefer
 III
,
Rev. Comput. Chem.
14
,
33
(
2000
).
24.
R. J.
Bartlett
and
M.
Musiał
,
Rev. Mod. Phys.
79
,
291
(
2007
).
25.
I.
Shavitt
and
R. J.
Bartlett
,
Many-Body Methods in Chemistry and Physics: MBPT and Coupled-Cluster Theory
(
Cambridge University Press
,
Cambridge
,
2009
).
26.
J.
Geertsen
,
M.
Rittby
, and
R. J.
Bartlett
,
Chem. Phys. Lett.
164
,
57
(
1989
).
27.
J. F.
Stanton
and
R. J.
Bartlett
,
J. Chem. Phys.
98
,
7029
(
1993
).
29.
R. J.
Bartlett
,
Wiley Interdiscip. Rev.: Comput. Mol. Sci.
2
,
126
(
2012
).
30.
J.
Liu
,
A.
Asthana
,
L.
Cheng
, and
D.
Mukherjee
,
J. Chem. Phys.
148
,
244110
(
2018
).
31.
M.
Hodecker
,
D. R.
Rehn
, and
A.
Dreuw
,
J. Chem. Phys.
152
,
094106
(
2020
).
32.
M.
Hodecker
,
S. M.
Thielen
,
J.
Liu
,
D. R.
Rehn
, and
A.
Dreuw
,
J. Chem. Theory Comput.
16
,
3654
(
2020
).
33.
F.
Mertins
and
J.
Schirmer
,
Phys. Rev. A
53
,
2140
(
1996
).
34.
F.
Mertins
,
J.
Schirmer
, and
A.
Tarantelli
,
Phys. Rev. A
53
,
2153
(
1996
).
35.
J.
Schirmer
and
F.
Mertins
,
Theor. Chem. Acc.
125
,
145
(
2010
).
36.
R. J.
Bartlett
,
S. A.
Kucharski
, and
J.
Noga
,
Chem. Phys. Lett.
155
,
133
(
1989
).
37.
A. G.
Taube
and
R. J.
Bartlett
,
J. Chem. Phys.
130
,
144112
(
2009
).
38.
J. D.
Watts
,
G. W.
Trucks
, and
R. J.
Bartlett
,
Chem. Phys. Lett.
164
,
502
(
1989
).
39.
J. D.
Watts
,
G. W.
Trucks
, and
R. J.
Bartlett
,
Chem. Phys. Lett.
157
,
359
(
1989
).
40.
F. A.
Evangelista
,
J. Chem. Phys.
134
,
224102
(
2011
).
41.
F.
Jensen
,
Introduction to Computational Chemistry
, 2nd ed. (
John Wiley & Sons
,
USA
,
2006
).
42.
G. W.
Trucks
,
E. A.
Salter
,
J.
Noga
, and
R. J.
Bartlett
,
Chem. Phys. Lett.
150
,
37
(
1988
).
43.
C. W.
Bauschlicher
and
P. R.
Taylor
,
Theor. Chim. Acta
71
,
263
(
1987
).
44.
C. W.
Bauschlicher
,
S. R.
Langhoff
, and
P. R.
Taylor
,
Adv. Chem. Phys.
77
,
103
(
1990
).
45.
M.
Wormit
,
D. R.
Rehn
,
P. H. P.
Harbach
,
J.
Wenzel
,
C. M.
Krauter
,
E.
Epifanovsky
, and
A.
Dreuw
,
Mol. Phys.
112
,
774
(
2014
).
46.
E.
Merzbacher
,
Quantum Mechanics
, 3rd ed. (
John Wiley & Sons, Inc.
,
New York
,
1998
).
47.
A.
Messiah
,
Quantum Mechanics
, Dover Books on Physics (
Dover Publications
,
1999
).
48.
I. N.
Levine
,
Quantum Chemistry
, 7th ed. (
Pearson Education
,
2013
).
49.
A.
Szabo
and
N. S.
Ostlund
,
Modern Quantum Chemistry: Introduction to Advanced Electronic Structure Theory
(
Dover
,
Mineola, NY
,
1996
).
50.
T.
Helgaker
,
P.
Jørgensen
, and
J.
Olsen
,
Molecular Electronic-Structure Theory
(
John Wiley & Sons, Ltd.
,
2000
).
51.
M. D.
Prasad
,
S.
Pal
, and
D.
Mukherjee
,
Phys. Rev. A
31
,
1287
(
1985
).
52.
D.
Mukherjee
and
W.
Kutzelnigg
, in
Many-Body Methods in Quantum Chemistry
, Lecture Notes in Chemistry, edited by
U.
Kaldor
(
Springer Berlin
,
Heidelberg
,
1989
), Vol. 52, pp.
257
274
.
53.
W.
Kutzelnigg
,
Theor. Chim. Acta
80
,
349
(
1991
).
54.
A. G.
Taube
and
R. J.
Bartlett
,
Int. J. Quantum Chem.
106
,
3393
(
2006
).
55.
W.
Kutzelnigg
and
S.
Koch
,
J. Chem. Phys.
79
,
4315
(
1983
).
56.
M. R.
Hoffmann
and
J.
Simons
,
J. Chem. Phys.
88
,
993
(
1988
).
57.
W.
Kutzelnigg
,
J. Chem. Phys.
77
,
3081
(
1982
).
58.
J.
Schirmer
and
F.
Mertins
,
Int. J. Quantum Chem.
58
,
329
(
1996
).
59.
Y.
Shao
,
Z.
Gan
,
E.
Epifanovsky
,
A. T.
Gilbert
,
M.
Wormit
,
J.
Kussmann
,
A. W.
Lange
,
A.
Behn
,
J.
Deng
,
X.
Feng
,
D.
Ghosh
,
M.
Goldey
,
P. R.
Horn
,
L. D.
Jacobson
,
I.
Kaliman
,
R. Z.
Khaliullin
,
T.
Kús
,
A.
Landau
,
J.
Liu
,
E. I.
Proynov
,
Y. M.
Rhee
,
R. M.
Richard
,
M. A.
Rohrdanz
,
R. P.
Steele
,
E. J.
Sundstrom
,
H. L.
Woodcock
 III
,
P. M.
Zimmerman
,
D.
Zuev
,
B.
Albrecht
,
E.
Alguire
,
B.
Austin
,
G. J. O.
Beran
,
Y. A.
Bernard
,
E.
Berquist
,
K.
Brandhorst
,
K. B.
Bravaya
,
S. T.
Brown
,
D.
Casanova
,
C.-M.
Chang
,
Y.
Chen
,
S. H.
Chien
,
K. D.
Closser
,
D. L.
Crittenden
,
M.
Diedenhofen
,
R. A.
DiStasio
, Jr.
,
H.
Do
,
A. D.
Dutoi
,
R. G.
Edgar
,
S.
Fatehi
,
L.
Fusti-Molnar
,
A.
Ghysels
,
A.
Golubeva-Zadorozhnaya
,
J.
Gomes
,
M. W.
Hanson-Heine
,
P. H.
Harbach
,
A. W.
Hauser
,
E. G.
Hohenstein
,
Z. C.
Holden
,
T.-C.
Jagau
,
H.
Ji
,
B.
Kaduk
,
K.
Khistyaev
,
J.
Kim
,
J.
Kim
,
R. A.
King
,
P.
Klunzinger
,
D.
Kosenkov
,
T.
Kowalczyk
,
C. M.
Krauter
,
K. U.
Lao
,
A. D.
Laurent
,
K. V.
Lawler
,
S. V.
Levchenko
,
C. Y.
Lin
,
F.
Liu
,
E.
Livshits
,
R. C.
Lochan
,
A.
Luenser
,
P.
Manohar
,
S. F.
Manzer
,
S.-P.
Mao
,
N.
Mardirossian
,
A. V.
Marenich
,
S. A.
Maurer
,
N. J.
Mayhall
,
E.
Neuscamman
,
C. M.
Oana
,
R.
Olivares-Amaya
,
D. P.
O’Neill
,
J. A.
Parkhill
,
T. M.
Perrine
,
R.
Peverati
,
A.
Prociuk
,
D. R.
Rehn
,
E.
Rosta
,
N. J.
Russ
,
S. M.
Sharada
,
S.
Sharma
,
D. W.
Small
,
A.
Sodt
,
T.
Stein
,
D.
Stück
,
Y.-C.
Su
,
A. J.
Thom
,
T.
Tsuchimochi
,
V.
Vanovschi
,
L.
Vogt
,
O.
Vydrov
,
T.
Wang
,
M. A.
Watson
,
J.
Wenzel
,
A.
White
,
C. F.
Williams
,
J.
Yang
,
S.
Yeganeh
,
S. R.
Yost
,
Z.-Q.
You
,
I. Y.
Zhang
,
X.
Zhang
,
Y.
Zhao
,
B. R.
Brooks
,
G. K.
Chan
,
D. M.
Chipman
,
C. J.
Cramer
,
W. A.
Goddard
 III
,
M. S.
Gordon
,
W. J.
Hehre
,
A.
Klamt
,
H. F.
Schaefer
 III
,
M. W.
Schmidt
,
C. D.
Sherrill
,
D. G.
Truhlar
,
A.
Warshel
,
X.
Xu
,
A.
Aspuru-Guzik
,
R.
Baer
,
A. T.
Bell
,
N. A.
Besley
,
J.-D.
Chai
,
A.
Dreuw
,
B. D.
Dunietz
,
T. R.
Furlani
,
S. R.
Gwaltney
,
C.-P.
Hsu
,
Y.
Jung
,
J.
Kong
,
D. S.
Lambrecht
,
W.
Liang
,
C.
Ochsenfeld
,
V. A.
Rassolov
,
L. V.
Slipchenko
,
J. E.
Subotnik
,
T. V.
Voorhis
,
J. M.
Herbert
,
A. I.
Krylov
,
P. M.
Gill
, and
M.
Head-Gordon
,
Mol. Phys.
113
,
184
(
2015
).
60.
J. S.
Binkley
,
J. A.
Pople
, and
W. J.
Hehre
,
J. Am. Chem. Soc.
102
,
939
(
1980
).
61.
C. W.
Bauschlicher
and
P. R.
Taylor
,
J. Chem. Phys.
85
,
6510
(
1986
).
62.
C. W.
Bauschlicher
and
P. R.
Taylor
,
J. Chem. Phys.
86
,
1420
(
1987
).
63.
A. L.
Dempwolff
,
A. C.
Paul
,
A. M.
Belogolova
,
A. B.
Trofimov
, and
A.
Dreuw
,
J. Chem. Phys.
152
,
024113
(
2020
).
64.
T. H.
Dunning
,
J. Chem. Phys.
90
,
1007
(
1989
).
65.
R. A.
Kendall
,
T. H.
Dunning
, Jr.
, and
R. J.
Harrison
,
J. Chem. Phys.
96
,
6796
(
1992
).
66.
M.-L.
Hebestreit
,
M.
Schneider
,
H.
Lartian
,
V.
Betz
,
M.
Heinrich
,
M.
Lindic
,
M. Y.
Choi
, and
M.
Schmitt
,
Phys. Chem. Chem. Phys.
21
,
14766
(
2019
).
67.
R. G.
Parr
and
W.
Yang
,
Density-Functional Theory of Atoms and Molecules
(
Oxford University Press
,
USA
,
1994
).
68.
A. D.
Becke
,
J. Chem. Phys.
98
,
5648
(
1993
).
69.
F.
Weigend
and
R.
Ahlrichs
,
Phys. Chem. Chem. Phys.
7
,
3297
(
2005
).
70.
C. A.
Burrus
,
J. Chem. Phys.
28
,
427
(
1958
).
71.
L.
Wharton
,
L. P.
Gold
, and
W.
Klemperer
,
J. Chem. Phys.
33
,
1255
(
1960
).
72.
D. K.
Coles
,
W. E.
Good
,
J. K.
Bragg
, and
A. H.
Sharbaugh
,
Phys. Rev.
82
,
877
(
1951
).
73.
K. P.
Huber
and
G.
Herzberg
,
Molecular Spectra and Molecular Structure. IV: Constants of Diatomic Molecules
(
Springer US
,
Boston, MA
,
1979
).
75.
B. N.
Bhattacharya
and
W.
Gordy
,
Phys. Rev.
119
,
144
(
1960
).
76.
J. M.
Brown
,
S. W.
Chalkley
, and
F. D.
Wayne
,
Mol. Phys.
38
,
1521
(
1979
).
77.
F. X.
Powell
and
D. R.
Lide
,
J. Chem. Phys.
42
,
4201
(
1965
).
78.
R.
Thomson
and
F. W.
Dalby
,
Can. J. Phys.
46
,
2815
(
1968
).
79.
J. A.
Hodgeson
,
E. E.
Sibert
, and
R. F.
Curl
,
J. Phys. Chem.
67
,
2833
(
1963
).
80.
P. H. P.
Harbach
,
M.
Wormit
, and
A.
Dreuw
,
J. Chem. Phys.
141
,
064113
(
2014
).
81.
M.-L.
Hebestreit
,
H.
Lartian
,
M.
Schneider
,
R.
Kühnemuth
,
A. Y.
Torres-Boy
,
S.
Romero-Servin
,
J. A.
Ruiz-Santoyo
,
L.
Alvarez-Valtierra
,
W. L.
Meerts
, and
M.
Schmitt
,
J. Mol. Struct.
1210
,
127992
(
2020
).
82.
M.
Schmitt
and
L.
Meerts
, in
Frontiers and Advances in Molecular Spectroscopy
, edited by
J.
Laane
(
Elsevier
,
2018
), Chap. 5, pp.
143
193
.
You do not currently have access to this content.