The convergence of nucleus-centered multipolar expansion of the quantum-chemical electron density (QC-ED), gradient, and Laplacian is investigated in terms of numerical radial functions derived by projecting stockholder atoms onto real spherical harmonics at each center. The partial sums of this exact one-center expansion are compared with the corresponding Hansen-Coppens pseudoatom (HC-PA) formalism [Hansen, N. K. and Coppens, P., “Testing aspherical atom refinements on small-molecule data sets,” Acta Crystallogr., Sect. A 34, 909–921 (1978)] commonly utilized in experimental electron density studies. It is found that the latter model, due to its inadequate radial part, lacks pointwise convergence and fails to reproduce the local topology of the target QC-ED even at a high-order expansion. The significance of the quantitative agreement often found between HC-PA-based (quadrupolar-level) experimental and extended-basis QC-EDs can thus be challenged.

1.
N. K.
Hansen
and
P.
Coppens
, “
Testing aspherical atom refinements on small-molecule data sets
,”
Acta Crystallogr., Sect. A
34
,
909
921
(
1978
).
2.
M.
Born
and
K.
Huang
,
Dynamical Theory of Crystal Lattices
(
Oxford University Press
,
1954
).
3.
R. F.
Stewart
, “
Vibrational averaging of x-ray-scattering intensities
,”
Isr. J. Chem.
16
,
137
143
(
1977
).
4.
J. R.
Michael
and
T.
Koritsanszky
, “
Validation of convolution approximation to the thermal-average electron density
,”
J. Math. Chem.
53
,
250
259
(
2015
).
5.
R. F.
Stewart
, “
One-electron density functions and many-centered finite multipole expansions
,”
Isr. J. Chem.
16
,
124
131
(
1977
).
6.
R. F. W.
Bader
,
Atoms in Molecules: A Quantum Theory
, 1st ed., No. 22 in International Series of Monographs on Chemistry (
Clarendon Press
,
Oxford, U.K
,
1990
).
7.
T.
Koritsanszky
and
P.
Coppens
, “
Chemical applications of x-ray charge density analysis
,”
Chem. Rev.
101
,
1583
1627
(
2001
).
8.
Electron Density and Chemical Bonding I. Experimental Electron Densities
, Structure and Bonding, edited by
D.
Stalke
(
Springer-Verlag
,
Berlin-Heiderberg
,
2012
), Vol. 146.
9.
Applications of Topological Methods in Molecular Chemistry
, Challenges and Advances in Computational Chemistry and Physics, edited by
R.
Chauvin
,
C.
Lepetit
,
B.
Silvi
, and
E.
Alikhani
(
Springer
,
Switzerland
,
2016
), Vol. 22.
10.
S.
Grabowsky
,
T.
Pfeuffer
,
W.
Morgenroth
,
C.
Paulmann
,
T.
Schirmeister
, and
P. A.
Luger
, “
Comparative study on the experimentally derived electron densities of three protease inhibitor model compounds
,”
Org. Biomol. Chem.
6
,
2295
2307
(
2008
).
11.
B.
Engels
,
T. C.
Schmidt
,
C.
Gatti
,
T.
Schirmeister
, and
R. F.
Fink
, “
Challenging problems in charge density determination: Polar bonds and influence of the environment
,” in
Structure and Bonding II
, edited by
D.
Stalke
(
Springer-Verlag
,
Berlin-Heidelberg
,
2012
), Vol. 147, pp.
47
98
.
12.
E. R.
Johnson
,
S.
Keinan
,
P.
Mori-Sanchez
,
J.
Contreras-Garcia
,
A. J.
Cohen
, and
W.
Yang
, “
Revealing noncovalent interactions
,”
J. Am. Chem. Soc.
132
,
6498
6506
(
2010
).
13.
C.
Gatti
, “
The source function descriptor as a tool to extract chemical information from theoretical and experimental electron densities
,” in
Structure and Bonding II
, edited by
D.
Stalke
(
Springer-Verlag
,
Berlin-Heidelberg
,
2012
), Vol. 147, pp.
193
286
.
14.
V. G.
Tsirelson
and
A. I.
Stash
, “
On functions and quantities derived from the experimental electron density
,”
Acta Crystallogr., Sect. A: Found. Crystallogr.
60
,
418
426
(
2004
).
15.
E. A.
Zhurova
,
V. V.
Zhurov
, and
A. A.
Pinkerton
, “
Structure and bonding in β-HMX-characterization of a trans-annular N···N interaction
,”
J. Am. Chem. Soc.
129
,
13887
13893
(
2007
).
16.
D. V.
Gibbs
,
R. T.
Downs
,
D. F.
Cox
,
K. M.
Rosso
,
N. L.
Ross
,
A.
Kirfel
,
T.
Lippmann
,
W.
Morgenroth
, and
T. D.
Crawford
, “
Experimental bond critical point and local energy density properties determined for Mn—O, Fe—O, and Co—O bonded interactions for tephroite, Mn2SiO4, fayalite, Fe2SiO4, and Co2SiO4 olivine and selected organic metal Complexes: Comparison with properties calculated for non-transition and transition metal M—O bonded interactions for silicates and oxides
,”
J. Phys. Chem. A
112
,
8811
8823
(
2008
).
17.
J. R.
Michael
and
T.
Koritsanszky
, “
Computational analysis of thermal-motion effects on the topological properties of the electron density
,”
Acta Crystallogr., Sect. A: Found. Adv.
71
,
225
234
(
2015
).
18.
T.
Koritsanszky
and
A.
Volkov
, “
Density radial functions for bonded atoms
,”
Chem. Phys. Lett.
385
,
431
434
(
2004
).
19.
T.
Koritsanszky
,
A.
Volkov
, and
M.
Chodkiewicz
, “
New directions in pseudoatom-based x-ray charge density analysis
,” in
Structure and Bonding II
, edited by
D.
Stalke
(
Springer-Verlag
,
Berlin-Heidelberg
,
2012
), Vol. 147, pp.
1
16
.
20.
J. R.
Michael
and
A.
Volkov
, “
Density and wavefunction-normalized Cartesian spherical harmonics for l ≤ 20
,”
Acta Crystallogr., Sect. A: Found. Adv.
71
,
245
249
(
2015
).
21.
J. M.
Perez-Jorda
,
E.
San-Fabian
, and
F. A.
Moscardo
, “
Simple, reliable and efficient scheme for automatic numerical integration
,”
Comput. Phys. Commun.
70
,
271
284
(
1992
).
22.
O.
Treutler
and
R.
Ahlrichs
, “
Efficient molecular numerical integration schemes
,”
J. Chem. Phys.
102
,
346
354
(
1995
).
23.
V. I.
Lebedev
and
D. N.
Laikov
, “
A quadrature formula for the sphere of the 131st algebraic order of accuracy
,”
Dokl. Math.
59
,
477
481
(
1999
).
24.
T.
Kato
, “
On the eigenfunctions of many-particle systems in quantum mechanics
,”
Commun. Pure Appl. Math.
10
,
151
177
(
1957
).
25.
W. A.
Bingel
, “
The behavior of the first-order density matrix at the Coulomb singularities of the Schrödinger equation
,”
Z. Naturforsch., A
18
,
1249
1253
(
1963
).
26.
F. L.
Hirshfeld
, “
Bonded-atom fragments for describing molecular charge densities
,”
Theor. Chim. Acta
44
,
129
138
(
1977
).
27.
D.
Jayatilaka
and
B.
Dittrich
, “
X-ray structure refinement using aspherical atom density functions obtained from quantum chemical calculations
,”
Acta Crystallogr., Sect. A: Found. Crystallogr.
64
,
383
393
(
2008
).
28.
S. C.
Capelli
,
H.-B.
Bürgi
,
B.
Dittrich
, and
D
Jayatilaka
, “
Hirshfeld atom refinement
,”
IUCrJ.
1
,
361
379
(
2014
).
29.
E.
Clementi
and
C.
Roetti
,
At. Data Nucl. Data Tables
14
,
177
478
(
1974
).
30.
R. F.
Stewart
, “
Electron population analysis with rigid pseudoatoms
,”
Acta Crystallogr., Sect. A
32
,
565
574
(
1976
).
31.
J.
Autschbach
and
W. H. E.
Schwarz
, “
Where do the forces in molecules come from? A density functional study of N2 and HCl
,”
J. Phys. Chem. A
104
,
6039
6046
(
2000
).
32.
N.
Bindzus
,
T.
Straaso
,
N.
Wahlberg
,
J.
Becker
,
L.
Bjerg
,
N.
Lock
,
A. C.
Dippel
, and
B. B.
Iversen
, “
Experimental determination of core electron deformation in diamond
,”
Acta Crystallogr., Sect. A: Found. Adv.
70
,
39
48
(
2014
).
33.
P.-O.
Löwdin
, “
On the non-orthogonality problem connected with the use of atomic wave functions in the theory of molecules and crystals
,”
J. Chem. Phys.
18
,
365
375
(
1950
).
34.
J. W.
Bats
,
P.
Coppens
, and
T. F.
Koetzle
, “
The experimental charge density in sulfur-containing molecules. A study of the deformation electron density in sulfamic acid at 78 K by x-ray and neutron diffraction
,”
Acta Crystallogr., Sect. B: Struct. Crystallogr. Cryst. Chem.
33
,
37
45
(
1977
).
35.
G.
te Velde
,
F. M.
Bickelhaupt
,
E. J.
Baerends
,
C.
Fonseca Guerra
,
S. J. A.
van Gisbergen
,
J. G.
Snijders
, and
T.
Ziegler
, “
Chemistry with ADF
,”
J. Comput. Chem.
22
,
931
967
(
2001
).
36.
C.
Lee
,
W.
Yang
, and
R. G.
Parr
, “
Development of the Colle-Salvetti correlation-energy formula into a functional of the electron density
,”
Phys. Rev. B
37
,
785
789
(
1988
).
37.
A. D.
Becke
, “
Density-functional exchange-energy approximation with correct asymptotic-behavior
,”
Phys. Rev. A
38
,
3098
3100
(
1988
).
38.
E. V.
van Lenthe
and
E. J.
Baerends
, “
Optimized slater-type basis sets for the elements 1-118
,”
J. Comput. Chem.
24
,
1142
1156
(
2003
).
39.
M. J.
Frisch
,
G. W.
Trucks
,
H. B.
Schlegel
,
G. E.
Scuseria
,
M. A.
Robb
,
J. R.
Cheeseman
,
G.
Scalmani
,
V.
Barone
,
B.
Mennucci
,
G. A.
Petersson
,
H.
Nakatsuji
,
M.
Caricato
,
X.
Li
,
H. P.
Hratchian
,
A. F.
Izmaylov
,
J.
Bloino
,
G.
Zheng
,
J. L.
Sonnenberg
,
M.
Hada
,
M.
Ehara
,
K.
Toyota
,
R.
Fukuda
,
J.
Hasegawa
,
M.
Ishida
,
T.
Nakajima
,
Y.
Honda
,
O.
Kitao
,
H.
Nakai
,
T.
Vreven
,
J. A.
Montgomery
, Jr.
,
J. E.
Peralta
,
F.
Ogliaro
,
M.
Bearpark
,
J. J.
Heyd
,
E.
Brothers
,
K. N.
Kudin
,
V. N.
Staroverov
,
R.
Kobayashi
,
J.
Normand
,
K.
Raghavachari
,
A.
Rendell
,
J. C.
Burant
,
S. S.
Iyengar
,
J.
Tomasi
,
M.
Cossi
,
N.
Rega
,
J. M.
Millam
,
M.
Klene
,
J. E.
Knox
,
J. B.
Cross
,
V.
Bakken
,
C.
Adamo
,
J.
Jaramillo
,
R.
Gomperts
,
R. E.
Stratmann
,
O.
Yazyev
,
A. J.
Austin
,
R.
Cammi
,
C.
Pomelli
,
J. W.
Ochterski
,
R. L.
Martin
,
K.
Morokuma
,
V. G.
Zakrzewski
,
G. A.
Voth
,
P.
Salvador
,
J. J.
Dannenberg
,
S.
Dapprich
,
A. D.
Daniels
,
Ö.
Farkas
,
J. B.
Foresman
,
J. V.
Ortiz
,
J.
Cioslowski
, and
D. J.
Fox
, gaussian 09, Revision E.01,
Gaussian, Inc.
,
Wallingford, CT
,
2009
.
40.
A.
Volkov
,
T.
Koritsanszky
,
M.
Chodkiewicz
, and
H. F
King
, “
On the basis-set dependence of local and integrated electron density properties: Application of a new computer program for quantum-chemical density analysis
,”
J. Comput. Chem.
30
,
1379
1391
(
2009
).
41.
J. R.
Michael
, “
Analysis of thermal motion effects on the electron density via computational simulations
,” Ph.D. thesis,
Middle Tennessee State University
,
2014
.
42.
T.
Koritsanszky
,
D.
Zobel
, and
P.
Luger
, “
Topological analysis of experimental electron densities 3. Hydrogen (+)-Tartrate at 15K
,”
J. Phys. Chem. A
104
,
1549
1556
(
2000
).
43.
L. J.
Farrugia
and
C.
Evans
, “
Experimental x-ray charge density studies on the binary carbonyls Cr(CO)6, Fe(CO)5, and Ni(CO)4
,”
J. Phys. Chem. A
109
,
8834
8848
(
2005
).
44.
J.
Overgaard
,
H. F.
Clausen
,
J. A.
Platts
, and
B. B.
Iversen
, “
Experimental and theoretical charge density study of chemical bonding in a Co dimer complex
,”
J. Am. Chem. Soc.
130
,
3834
3843
(
2008
).
45.
J. J.
Dua
,
L.
Váradia
,
J.
Tana
,
Y.
Zhaoa
,
P. W.
Groundwatera
,
J. A.
Plattsb
, and
D. E.
Hibbs
, “
Experimental and theoretical charge density distribution in pigment yellow 101
,”
Phys. Chem. Chem. Phys.
17
,
4677
4686
(
2015
).
46.
I.
Bytheway
,
S. G.
Chandler
, and
B. N.
Figgis
, “
Can a multipole analysis faithfully reproduce topological descriptors of a total charge density?
,”
Acta Crystallogr., Sect. A: Found. Crystallogr.
58
,
451
459
(
2002
).
47.
A.
Volkov
and
P.
Coppens
, “
Critical examination of the radial functions in the Hansen-Coppens multipole model through topological analysis of primary- and refined- theoretical densities
,”
Acta Crystallogr., Sect. A: Found. Crystallogr.
57
,
395
405
(
2001
).
48.
A.
Volkov
,
Y. A.
Abramov
, and
P.
Coppens
, “
Density optimized radial exponents for x-ray charge density refinement from ab initio calculations
,”
Acta Crystallogr., Sect. A: Found. Crystallogr.
57
,
272
282
(
2001
).

Supplementary Material

You do not currently have access to this content.