This thesis investigates the fundamental chemical properties of atmospheric gases and their impacts on ice formation dynamics in clouds at or near the upper troposphere and lower stratosphere (UTLS). Two overarching questions frame the research: (1) What fundamental chemical properties of gas molecules can be used to predict how gases will be retained in a water droplet when it starts to freeze? And (2) How do hydrogen and halogen bond interactions between atmospheric gases and water affect the freezing process in cloud droplets?To address these questions, three thesis chapters offer unique insights into the chemical mechanisms governing cloud freezing processes at a molecular level. A common thread throughout the thesis is the use of molecular dynamics simulations to provide molecular and mechanistic insights into how different gas species interact with water molecules during cloud droplet freezing. Molecular dynamics analyses of hydrogen and halogen bonding relationships of gases with water, freezing rates of synthetic water droplets with gas inclusions, and potential of mean force profiles of gases across ice/water and air/water interfaces are integrated to gain never-before-seen insights into the precise dynamics of gas molecule-mediated phenomena during the cloud freezing process. Key findings from the studies include the destabilization of ice matrices by halogen bonding, the role of highly polar gases as molecular catalysts in accelerating ice freezing in the atmosphere, and potential gas-mediated mechanisms spurring the formation of Quasi-Liquid Layer (QLL) surfaces in clouds. All experimental studies have been at a macroscopic level with no insight into the molecular underpinnings of how cloud freezing works. Findings from the molecular dynamics studies from this thesis have provided insight into cloud freezing processes at a molecular level for the first time.