Inhomogeneity of the amorphous solid water dangling bonds

Area of Science:

• Materials Science
• Surface Chemistry
• Astrochemistry

Background:

• Amorphous solid water (ASW) is crucial for interstellar medium and Earth's upper atmosphere.
• ASW's bulk and surface are studied, but changes from perturbations like IR irradiation are not fully understood.
• Surface adsorption and reactivity of ASW influence the formation of complex molecules.

Purpose of the Study:

• Investigate the structure and inhomogeneity of dangling bonds on ASW surfaces.
• Understand the effects of mid-infrared (IR) irradiation on ASW surface properties.
• Determine the impact of irradiation duration on surface reorientation and isomerisation.

Main Methods:

• Selective mid-IR irradiation of ASW surfaces.
• Analysis of dangling bond structures and their homogeneity.
• Monitoring surface reorientation and photoinduced isomerisation yields.

Main Results:

• Selective IR irradiations demonstrate the inhomogeneity of dH dangling bonds on ASW surfaces.
• Surface reorientation and isomerisation were observed upon irradiation.
• Maximum photoinduced isomerisation yield was determined to be approximately 15%.

Conclusions:

• The dangling bonds on ASW surfaces exhibit inhomogeneous vibrational modes.
• Mid-IR irradiation induces changes in ASW surface structure and molecular orientation.
• Understanding these surface dynamics is key to comprehending ASW's role in chemical evolution.