Chapter 1
The Electronic Structure Determination
This is a peculiar physical problem, and only later in the time, compared with the
atomic structure determination by physical scientists, the chemists investigated the
molecular case study. Expectedly during the time, the preferential object for chemists has been focused on the rationale of the reactivity, where a number of
experimental data are available. The electronic structure of the molecules, mainly of
inorganic ones, slowly began to be investigated.
Starting from this situation and in order to approach the electronic structure
determination, the following pathway is proposed:
(i) The Schrodinger equation HW n = EW n is very difficult to be resolved for a
molecular system, being the E n values
E n ¼ W
Ã
n jHjW n
= W
Ã
n jW n
impossible to be calculated in the absence of H and W n expressions.
(ii) Hypotheses on W n and/or H have to be made in order to optimize W n by
variation or perturbation methods.
(iii) The eigenvalues of the Schrödinger equation are calculated by assuming
approximated values of the integral W
Ã
n jHjW n
, in agreement with the
peculiar properties of the compound.
(iv) The calculated eigenvalues are compared with the experimental ones, derived
from electronic spectra, in order to obtain structure–chemical property
relations.
© Springer Nature Switzerland AG 2021
F. Morazzoni, Symmetry in Inorganic and Coordination Compounds, Lecture Notes
in Chemistry 106, https://doi.org/10.1007/978-3-030-62996-0_1
1
The Electronic Structure Determination
This is a peculiar physical problem, and only later in the time, compared with the
atomic structure determination by physical scientists, the chemists investigated the
molecular case study. Expectedly during the time, the preferential object for chemists has been focused on the rationale of the reactivity, where a number of
experimental data are available. The electronic structure of the molecules, mainly of
inorganic ones, slowly began to be investigated.
Starting from this situation and in order to approach the electronic structure
determination, the following pathway is proposed:
(i) The Schrodinger equation HW n = EW n is very difficult to be resolved for a
molecular system, being the E n values
E n ¼ W
Ã
n jHjW n
= W
Ã
n jW n
impossible to be calculated in the absence of H and W n expressions.
(ii) Hypotheses on W n and/or H have to be made in order to optimize W n by
variation or perturbation methods.
(iii) The eigenvalues of the Schrödinger equation are calculated by assuming
approximated values of the integral W
Ã
n jHjW n
, in agreement with the
peculiar properties of the compound.
(iv) The calculated eigenvalues are compared with the experimental ones, derived
from electronic spectra, in order to obtain structure–chemical property
relations.
© Springer Nature Switzerland AG 2021
F. Morazzoni, Symmetry in Inorganic and Coordination Compounds, Lecture Notes
in Chemistry 106, https://doi.org/10.1007/978-3-030-62996-0_1
1