Proton tunneling in low dimensional cesium silicate LDS-1

Area of Science:

• Solid State Chemistry
• Materials Science
• Spectroscopy

Background:

• Low-dimensional cesium silicate LDS-1 exhibits unique properties due to its structure.
• Proton dynamics and hydrogen bonding significantly influence material characteristics.

Purpose of the Study:

• To investigate anomalous infrared absorption bands in LDS-1.
• To assign these bands to specific proton vibrational modes.
• To understand the role of proton tunneling and hydrogen bonding at low temperatures.

Main Methods:

• Infrared absorption spectroscopy at varying temperatures.
• Analysis of integrated absorbance using anharmonic double-minimum potentials.
• Theoretical modeling of proton interactions and vibrational modes.

Main Results:

• Observed absorption bands at 93, 155, 1210, and 1220 cm(-1) assigned to proton vibrational modes.
• Enhanced absorbance at low temperatures indicates increased proton activity.
• Proton tunneling leads to ground state energy splitting, observed as optical transitions.
• Symmetric and asymmetric vibrational modes identified due to Coulomb interactions between protons.
• Collective modes involving silicate chain, Cs(+) ions, and proton oscillations emerge.

Conclusions:

• Proton tunneling is a key mechanism governing the observed infrared spectra in LDS-1.
• Hydrogen bonding strength and proton dynamics are temperature-dependent.
• The study provides insights into the complex interplay of ionic and protonic vibrations in low-dimensional silicates.