REAKTIVITAS ION KALSIUM(II) DALAM AMONIAK CAIR: STUDI SIMULASI DINAMIKA MOLEKULER QUANTUM MECHANICAL CHARGE FIELD (QMCF); REACTIVITY OF CALCIUM(II) ION IN LIQUID AMMONIA: MOLECULAR DYNAMICS SIMULATION STUDY OF QUANTUM MECHANICAL CHARGE FIELD (QMCF)

UTAMI, WIJI, Ria Armunanto

2016 | Disertasi | FMIPA

Reactivity of Ca2+ ion in liquid ammonia has been investigated using QMCFMD method. The QMCF-MD method is a framework based on a partitioning scheme which effectively divides the system of study into two regions. The first one contains the chemically interesting species, solvated ion and its first solvation shell, which are treated by quantum mechanics, and the remaining part of the system is treated classically. The aim of this study is to determine the reactivity of Ca2+ ion solvation system in liquid ammonia based on radial distribution function, coordination number distribution, angular distribution function, mean residence time and ion-ammonia vibrational frequencies analysis. Ab initio HF/SV(P) and DZP Dunning methods were validated by calculating BSSE energy. The system was equilibrated for 3 ps at 235.15 K, then sampling data was collected every fifth step during simulation time of 12 ps. Result of the study showed that the labile first solvation shell was observed containing of 7-8 ammonia molecules. Mean residence time of ligand in the first solvation shell was 14.45 ps showing few exchanges with second solvation shell. The results show in a good agreement with previous reports both experimental and theoretical studies.

Kata Kunci : liquid ammonia; Ca2+ ion; Reactivity; MD-QMCF