Spectroscopic Evidence for a Dinitrogen Complex of Gallium and Estimation of the GaN 2 Bond Strength

Matrix‐isolation experiments were performed to study the interaction between Ga atoms and N 2 by using Raman and UV/Vis spectroscopies for detection and analysis. It was revealed that a weak complex is formed, for which resonance Raman spectra were obtained. Several overtones were sighted, allowing a rough estimate of the GaN 2 fragmentation energy to be made (∼19 kJ mol −1 ). The excitation profile obtained from the spectra at different laser wavelengths agrees with the UV/Vis spectrum and shows that the complex exhibits an electronic transition at around 410 nm. At the Ga atom, this transition can be described as a 2 S← 2 P or 2 D← 2 P excitation, which is red‐shifted from its position for free Ga atoms (approximately 340 nm and 270 nm for 2 S← 2 P and 2 D← 2 P, respectively) as a result of N 2 complexation. The effect of complexation involves, therefore, only slight stabilization of the 2 P ground state but relatively strong stabilization of the excited 2 S state. Accordingly, for the Ga atom in its excited 2 S state, the GaN 2 bond energy can be estimated to be around 79 kJ mol −1 .