KAJIAN TEORITIS SIFAT STRUKTUR DAN DINAMIKA ION Sc+ SINGLET (1D) DAN TRIPLET (3D) DALAM AIR, AMONIAK CAIR, DAN CAMPURAN AMONIAK-AIR MENGGUNAKAN SIMULASI DINAMIKA MOLEKULER AB INITIO MEKANIKA KUANTUM/MEKANIKA MOLEKULER; THEORETICAL STUDY OF STRUCTURAL AND DYNAMICAL PROPERTIES OF SINGLET (1D) AND TRIPLET (3D) IONS IN WATER, LIQUID AMMONIA AND AMMONIA-WATER MIXTURE USING MOLECULAR DYNAMICS SIMULATION OF AB INITIO QUANTUM MECHANICS/ MOLECULAR MECHANICS

Partama, Crys Fajar, Ria Armunanto

2015 | Tesis | FMIPA

Structural and dynamical solvation properties of Sc+ singlet (1D) and Sc+ triplet (3D) ions in water, liquid ammonia and ammonia-water mixture have been studied using quantum mechanics/molecular mechanics molecular dynamics (QM/MM MD) simulation. The basis set Lanl2dz ecp was used for Sc+ singlet (1D) and Sc+ triplet (3D) ions, while DZP (Dunning) for N, O, and H atoms QM/MM MD simulation ion in water was conducted under one ion in 499 water molecule, at temperature 298.16 K, in accordance with density of water 0.9907 g cm-3. QM/MM MD simulation in liquid ammonia was performed under one ion in 215 ammonia at temperature 235.26 K, in accordance with the density of liquid ammonia 0.690 g cm-3. QM/MM MD simulation in ammonia-water mixture was conducted under one ion in mixture of 92 ammonia and 407 water molecules at temperature of 298.16 K, in accordance with the density of ammonia-water mixture 0.9270 g cm-3 and a concentration of 18.6% ammonia QM/MM MD simulation of Sc+ singlet (1D) and Sc+ triplet (3D) ions in water, liquid ammonia and ammonia-water mixture are performed about 25 ps obtaining the following results. First solvation structures of ion in water show Sc+ singlet (1D) binds 3 molecules of water, meanwhile the Sc+ triplet (3D) two water molecules. Both structures of the first solvation shells are rigids. The first solvation shell structures of ion in liquid ammonia show Sc+ singlet (1D) binds 3 molecules of ammonia, meanwhile Sc+ triplet (3D) two ammonia molecules. Both structures are also rigids. The first solvation shell structure of Sc+ singlet (1D) ion in ammonia-water mixture is composed [Sc(NH3)2(H2O)2]+ and [Sc(NH3)2(H2O)3]+ complex, meanwhile Sc+ triplet (3D) ion in ammonia-water mixture shows [Sc(NH3)2(H2O)]+ and [Sc(NH3)2(H2O)2]+ complex structure. Solvation structures of Sc+ singlet (1D) and Sc+ triplet (3D) ions with ammonia are rigid, meanwhile Sc+ singlet (1D) and Sc+ triplet (3D) ions with water are dynamic, due to the occurrence of ligand exchanges during simulation time.

Kata Kunci : QM/MM MD; Sc+ singlet (1D); Sc+ triplet (3D); water; ammonia.