Description
Water molecules play a central role in many physical, chemical, and biological processes. In particular, the behavior of water near solid surfaces strongly influences phenomena such as surface chemistry, catalysis, and interfacial phase transitions. When a water molecule approaches a surface, interactions with the surrounding environment can modify its structure and dynamics compared with its behavior in free space. In free space, the vibrational motion of a water molecule is well understood. Due to its molecular symmetry, water exhibits a small number of characteristic vibrational modes, including symmetric stretching, asymmetric stretching, and bending vibrations. These modes are commonly described using methods from Molecular Physics and Normal Mode Analysis. However, when a molecule interacts with a nearby surface, the symmetry of the system can be broken by anisotropic forces, potentially altering the vibrational frequencies and coupling between modes. In this work, we investigate how the vibrational properties of a single water molecule change when it is placed near a model surface potential. We first analyze the vibrational frequencies and normal modes of the isolated molecule. We then introduce a simplified one-dimensional anisotropic potential representing the influence of a nearby surface and examine how this perturbation modifies vibrational behavior. The analysis is performed using a simplified classical framework based on small oscillations and basic methods from Lagrangian Mechanics. By comparing the vibrational spectra of the free and surface-confined molecule, this study illustrates how surface interactions break molecular symmetry and alter vibrational dynamics. These results provide a conceptual starting point for understanding why water near interfaces often exhibits unusual behavior, including modified phase transitions, enhanced chemical reactivity, and proton transfer processes. The framework developed here offers a foundation for future studies of interfacial water and surface-driven molecular phenomena.