1 3
Theor Chem Acc (2015) 134:117
DOI 10.1007/s00214-015-1717-4
REGULAR ARTICLE
Atoms and bonds in molecules: topology and properties
Jessica E. Besaw
1 · Peter L. Warburton
1 · Raymond A. Poirier
1
Received: 12 June 2015 / Accepted: 1 September 2015 / Published online: 18 September 2015
© Springer-Verlag Berlin Heidelberg 2015
Keywords Atoms in molecules · Bonds in molecules ·
Molecular radial electron density · Topology
1 Introduction
The concept of atoms and bonds is ubiquitously employed
to predict, interpret, and communicate chemistry [ 2 ]. In
pursuit of a well-defi ned molecular atom, numerous atoms
in molecules (AIM) theories were developed [ 1 , 3 – 5 ]. An
AIM theory partitions the molecular electron density into
atomic contributions, revealing the properties of each
molecular atom [ 3 ]. One downfall of most AIM theories is
that they fail to explicitly defi ne the bond. In this paper, we
seek to develop an atoms and bonds in molecules (ABIM)
theory that elucidates the physical and chemical properties
of both molecular atoms and bonds.
There are many benefi ts to quantify atoms and bonds.
One motivation for defi ning molecular atoms is the potential to construct the electron density of larger molecules
from a database of appropriate AIM representations, thus
greatly reducing computational time and cost [ 1 ]. Furthermore, if molecules can be built from AIM representations,
it follows that molecular properties could be determined as
a combination of AIM properties [ 1 ]. We are also motivated
to quantify the physical and chemical properties of the
bond, such as number of electrons, strength, order (single,
double, or triple), type (ionic or covalent), shape, and volume. With this knowledge, we can acquire greater insight
into chemical reactions by noting changes in the molecular
atom and bond properties.
Many approaches have been developed to defi ne atoms
in molecules [ 3 , 6 ], resulting in much debate about which
model is the most realistic. One contentious issue is
whether or not the electron density of the AIM overlaps.
Abstract The atoms and bonds in molecules (ABIM) theory Warburton et al. (J Phys Chem A 115:852, 2011 ) partitions the molecular electron density into atomic and bonding regions using radial density. The concept is motivated
by the radial distribution function of atoms which exhibit
shell structure, where each shell contains a realistic number of electrons. In this paper, we defi ne molecular radial
density and investigate its topology in 2D planes of halogens, diatomics, and hydrides. The terminology employed
to classify the radial density topology of atoms and molecules is then presented. The ABIM model quantifi es both
the molecular atom and bond. Here, we describe and calculate properties of ABIM and discuss how these properties
correlate with expected trends. ABIM makes it possible to
calculate the properties of atoms and bonds in molecules
including number of electrons, shape, volume, dipole, and
expectation values. The radial density model provides an
intuitive description of ABIM.
Published as part of the special collection of articles “Festschrift
in honour of P. R. Surjan”.
Electronic supplementary material The online version of this
article (doi: 10.1007/s00214-015-1717-4 ) contains supplementary
material, which is available to authorized users.
* Raymond A. Poirier
rpoirier@mun.ca
Jessica E. Besaw
jeb150@mun.ca
Peter L. Warburton
peterw@mun.ca
1
Department of Chemistry , Memorial University , St. John’s ,
NL A1B 3X7 , Canada
57
Reprinted from the journal
Theor Chem Acc (2015) 134:117
DOI 10.1007/s00214-015-1717-4
REGULAR ARTICLE
Atoms and bonds in molecules: topology and properties
Jessica E. Besaw
1 · Peter L. Warburton
1 · Raymond A. Poirier
1
Received: 12 June 2015 / Accepted: 1 September 2015 / Published online: 18 September 2015
© Springer-Verlag Berlin Heidelberg 2015
Keywords Atoms in molecules · Bonds in molecules ·
Molecular radial electron density · Topology
1 Introduction
The concept of atoms and bonds is ubiquitously employed
to predict, interpret, and communicate chemistry [ 2 ]. In
pursuit of a well-defi ned molecular atom, numerous atoms
in molecules (AIM) theories were developed [ 1 , 3 – 5 ]. An
AIM theory partitions the molecular electron density into
atomic contributions, revealing the properties of each
molecular atom [ 3 ]. One downfall of most AIM theories is
that they fail to explicitly defi ne the bond. In this paper, we
seek to develop an atoms and bonds in molecules (ABIM)
theory that elucidates the physical and chemical properties
of both molecular atoms and bonds.
There are many benefi ts to quantify atoms and bonds.
One motivation for defi ning molecular atoms is the potential to construct the electron density of larger molecules
from a database of appropriate AIM representations, thus
greatly reducing computational time and cost [ 1 ]. Furthermore, if molecules can be built from AIM representations,
it follows that molecular properties could be determined as
a combination of AIM properties [ 1 ]. We are also motivated
to quantify the physical and chemical properties of the
bond, such as number of electrons, strength, order (single,
double, or triple), type (ionic or covalent), shape, and volume. With this knowledge, we can acquire greater insight
into chemical reactions by noting changes in the molecular
atom and bond properties.
Many approaches have been developed to defi ne atoms
in molecules [ 3 , 6 ], resulting in much debate about which
model is the most realistic. One contentious issue is
whether or not the electron density of the AIM overlaps.
Abstract The atoms and bonds in molecules (ABIM) theory Warburton et al. (J Phys Chem A 115:852, 2011 ) partitions the molecular electron density into atomic and bonding regions using radial density. The concept is motivated
by the radial distribution function of atoms which exhibit
shell structure, where each shell contains a realistic number of electrons. In this paper, we defi ne molecular radial
density and investigate its topology in 2D planes of halogens, diatomics, and hydrides. The terminology employed
to classify the radial density topology of atoms and molecules is then presented. The ABIM model quantifi es both
the molecular atom and bond. Here, we describe and calculate properties of ABIM and discuss how these properties
correlate with expected trends. ABIM makes it possible to
calculate the properties of atoms and bonds in molecules
including number of electrons, shape, volume, dipole, and
expectation values. The radial density model provides an
intuitive description of ABIM.
Published as part of the special collection of articles “Festschrift
in honour of P. R. Surjan”.
Electronic supplementary material The online version of this
article (doi: 10.1007/s00214-015-1717-4 ) contains supplementary
material, which is available to authorized users.
* Raymond A. Poirier
rpoirier@mun.ca
Jessica E. Besaw
jeb150@mun.ca
Peter L. Warburton
peterw@mun.ca
1
Department of Chemistry , Memorial University , St. John’s ,
NL A1B 3X7 , Canada
57
Reprinted from the journal