Studying the Physisorption and Reaction Between In₉SnO₁₅ Pyramid Nanocluster With Water Molecule via Transition State Theory

Authors

• Nisreen A. Fejer, Department of Physics, College of Science, University of Al Nahrain, Baghdad, Iraq AND Department of Physics, College of Women Science, University of Baghdad, Baghdad, IraqFollow
• Asmaa H. Mohammed, Department of Physics, College of Science, University of Al Nahrain, Baghdad, IraqFollow
• Mohammed T. Hussein, Department of Physics, College of Science, University of Baghdad, Baghdad, Iraq AND AL Nukhba University College, Baghdad, IraqFollow

Abstract

This study investigates two binary semiconductors, Sn₁₀O₁₅ and In₁₀O₁₅, to form a ternary In₉SnO₁₅, a potential indium tin oxide (ITO) pyramid nanocluster for a humidity sensor, using density functional theory and transition-state theory. B3LYP hybrid functional was applied with the 6-311G** basis set for light elements (H, O) and (SDD) basis set for heavy elements (In, Sn). Steady-state geometrical structures were obtained using a complementary program, Gaussian View 05, and the corresponding electronic properties. HOMO and LUMO were calculated via the Gaussian 09W software program to obtain the energy gap of Sn₁₀O₁₅, In₁₀O₁₅, and In₉SnO₁₅ pyramid nanoclusters, which were analyzed before and after adsorption (physisorption) with a single water molecule. Thermodynamic parameters such as enthalpy, entropy, and Gibbs free energy were calculated to evaluate the energetic feasibility of water interaction. The vibrational changes that followed the physisorption of water were analyzed by simulating the IR and Raman spectra. The simulations reveal that exposure to water leads to changes in the energy gap and electronic structure, and thus, it implies that the conductivity of indium tin oxide (ITO) would be reduced, which is a promising indicator for humidity sensing. The calculated Gibbs free energy as a function of the interaction coordinates between In₉SnO₁₅ and H₂O to give In₉SnO₁₆ and release H₂ with the required energy was 3.13 eV; the positive value of Gibbs free energy means an endergonic reaction, suggesting a thermodynamically stimulated pathway under standard conditions, also known as the photocatalysis process.

Keywords

DFT, Electronic and spectroscopic study, Humidity sensing, Indium tin oxide, Transition state theory

Subject Area

Physics

Article Type

Article

First Page

2105

Last Page

2116

Creative Commons License

This work is licensed under a Creative Commons Attribution 4.0 International License.

How to Cite this Article

Fejer, Nisreen A.; Mohammed, Asmaa H.; and Hussein, Mohammed T. (2026) "Studying the Physisorption and Reaction Between In₉SnO₁₅ Pyramid Nanocluster With Water Molecule via Transition State Theory," Baghdad Science Journal: Vol. 23: Iss. 6, Article 12.
DOI: https://doi.org/10.21123/2411-7986.5326