Structures, binding energies, temperature effects, infrared spectroscopy of [Mg(NH3 )n = 1-10 ]+ clusters from DFT and MP2 investigations.

The possible isomers of [Mg(NH3 )n = 1 - 10 ]+ clusters have been investigated using both M06-2X/6-31++G(d,p) and MP2/6-31++G(d,p) levels of theory. The isomeric distribution for each n size has been studied as a function of temperatures ranging from 25 to 400 K. To the best of our knowledge, for clusters size n > 6, this is the first theoretical study available in the literature. From the calculated values in the considered clusters and using a fitting procedure, we have evaluated the binding energies (-14.0 kcal/mol), clustering energies (-10.1 kcal/mol), clustering free energies (-2.8 kcal/mol), and clustering enthalpies (-10.3 kcal/mol). On the basis of our structural and infrared (IR) spectroscopy outcomes, we find that the first solvation shell can hold up to six ammonia molecules. © 2019 Wiley Periodicals, Inc.