Interfacial Vibrational Dynamics of Ice I_h and Liquid Water

Abstract

Insights into energy flow dynamics at ice surfaces are essential for understanding chemical dynamics relevant to atmospheric and geographical sciences. Here, employing ultrafast surface-specific spectroscopy, we report the interfacial vibrational dynamics of ice I h . A comparison to liquid water surfaces reveals accelerated vibrational energy relaxation and dissipation at the ice surface for hydrogen-bonded OH groups. In contrast, free-OH groups sticking into the vapor phase exhibit substantially slower vibrational dynamics on ice. The acceleration and deceleration of vibrational dynamics of these different OH groups at the ice surface are attributed to enhanced intermolecular coupling and reduced rotational mobility, respectively. Our results highlight the unique properties of free-OH groups on ice, putatively linked to the high catalytic activities of ice surfaces.

Interfacial Vibrational Spectroscopy of the Water Bending Mode on Ice Ih

“…The averaged sample spectrum was background-subtracted and then normalized using a reference z-cut quartz spectrum measured in SSP polarization. Data in the stretch mode were collected on a different setup, the details of which are mentioned in the Supporting Information of our previous work …”

“…Data in the stretch mode were collected on a different setup, the details of which are mentioned in the Supporting Information of our previous work. 29 The ice sample for the infrared measurements is prepared by pressing a water droplet between two windows and placed in a cryostat. The infrared spectra are measured using a PerkinElmer 881 double-beam IR spectrometer.…”

Water Capture Mechanisms at Zeolitic Imidazolate Framework Interfaces

“…26,27 We find that ZIF-90 adsorbs water by mechanism 1. This study emphasizes the importance of interfacial-specific techniques, [28][29][30][31][32][33] determining that the competition between water-water and waterframework interactions dictates the uptake mechanism. Understanding ZIF-90 water uptake mechanism lays the foundation to further optimize its and other MOF's water harvesting function through post synthesis.…”

Water Capture Mechanisms at Zeolitic Imidazolate Framework Interfaces

“…This work is feasible by selectively probing the water clustering step, using a spatially-resolved vibrational sum-frequency generation (VSFG) spectroscopy and MB-pol [18][19][20] water-based simulations. 11 This study emphasizes the importance of interfacial-specific techniques [21][22][23][24][25][26] to decipher the effects of water-water and water-framework interactions on the water adsorption mechanism, which can provide guidance to the rational design of MOFs for water harvesting. Two crucial technical aspects that enable the micronresolved VSFG to probe adsorbed water at interior MOF surfaces.…”