<p>In
the present work, a computational study is performed in order to clarify the
possible magnetic nature of gold. For such purpose, gas phase Au<sub>2</sub>
(zero charge) is modelled, in order to calculate its gas phase formation
enthalpy. The calculated values were compared with the experimental value
obtained by means of Knudsen
effusion mass spectrometric studies [5]. Based on the obtained
formation enthalpy values for Au<sub>2</sub>, the compound with two unpaired
electrons is the most probable one. The calculated ionization energy of
modelled Au<sub>2</sub> with two unpaired electrons is 8.94 eV and with zero
unpaired electrons, 11.42 eV. The difference (11.42-8.94 = 2.48 eV = 239.29
kJmol<sup>-1</sup>), is in very good agreement with the experimental value of
226.2 ± 0.5 kJmol<sup>-1</sup> to the
Au-Au bond<sup>7</sup>. So, as expected, in the specie with none unpaired
electrons, the two 6s<sup>1</sup> (one of each gold atom) are paired, forming a
chemical bond with bond order 1. On the other hand, in Au<sub>2</sub> with two
unpaired electrons, the s-d hybridization prevails, because the relativistic
contributions. A molecular orbital energy diagram for gas phase Au<sub>2</sub>
is proposed, explaining its paramagnetism (and, by extension, the paramagnetism
of gold clusters and nanoparticles).</p>
Prediction on the multiplet energy diagram of α-Al2O3: Mn4+ under pressure
