Year: 2026
Type: preprint
Abstract: Measured evaporation branching ratios of partially deuterated isotopologues of protonated ammonia clusters (NH$_3$)$_N$ H$^+$ ($N \geq 8$) show ratios that depend only on the clusters' deuterium mole fraction. This demonstrates randomly distributed protium and deuterium in the molecules and can be used to determine free energy differences in the product cluster. The entropy thus determined is exclusively the deuterium-protium mixing entropy. The relative dissociation energies of the four isotopologues are determined and with the support of quantum chemistry calculations, their absolute values are estimated.
Source: arXiv (Cornell University)
Language: English
Subfield: Spectroscopy
Field: Chemistry
Domain: Physical Sciences
Open Access status: green
Funder: Austrian Science Fund
OpenAlex ID: W7213600123