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Article
Infrared spectroscopic study of hydrogen bonding topologies in the water octamer: The smallest ice cube
Xueming Yang
Dalian Institute of Chemical Physics
Corresponding Author
ORCiD: https://orcid.org/0000-0001-6684-9187
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This work is licensed under a CC BY 4.0 License. Read Full License
The water octamer, with its cubic structure consisting of six four-membered rings, presents an excellent system in which to unravel the cooperative interactions driven by subtle changes in the hydrogen-bonding topology. Although many distinct structures are calculated to exist, it has not been possible to extract the structural information encoded in their vibrational spectra because this requires size-selectivity of the neutral clusters with sufficient resolution to identify the contributions of the different isomeric forms. Here we report the size-specific infrared spectra of the isolated cold, neutral water octamer using a scheme based on threshold photoionization using a tunable vacuum ultraviolet free electron laser. A plethora of sharp vibrational bands features are observed for the first time. Theoretical analysis of these patterns reveals the coexistence of five cubic isomers, including two with chirality. The relative energies of these structures are found to reflect topology-dependent, delocalized multi-center hydrogen-bonding interactions. These results demonstrate that even with a common structural motif, the degree of cooperativity among the hydrogen-bonding network creates a hierarchy of distinct species. The implications of these results on possible metastable forms of ice are considered.
Keywords
water octamer, hydrogen bonding topology, sharp vibrational bands features, hydrogen-bonding network
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- WaterOctamerAnimationofvibrationalmodes20200804.pptx
Animation of vibrational modes of the Water Octamer
- WaterOctamerSI20200804.pdf
Supplementary information of the Water Octamer
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This is a preprint. It has not completed peer review.
Article
Infrared spectroscopic study of hydrogen bonding topologies in the water octamer: The smallest ice cube
Xueming Yang
Dalian Institute of Chemical Physics
Corresponding Author
ORCiD: https://orcid.org/0000-0001-6684-9187
Badges
Prescreen
This manuscript passed our Prescreen assessment
Complete author information
Appropriate declaration statements
Potential risks to human health
Prescreen
History
CURRENT STATUS: Posted
Version 1
Posted 12 Aug, 2020
Metrics
Comments: 0
PDF Downloads: ...
HTML Views: ...
License:
This work is licensed under a CC BY 4.0 License. Read Full License
The water octamer, with its cubic structure consisting of six four-membered rings, presents an excellent system in which to unravel the cooperative interactions driven by subtle changes in the hydrogen-bonding topology. Although many distinct structures are calculated to exist, it has not been possible to extract the structural information encoded in their vibrational spectra because this requires size-selectivity of the neutral clusters with sufficient resolution to identify the contributions of the different isomeric forms. Here we report the size-specific infrared spectra of the isolated cold, neutral water octamer using a scheme based on threshold photoionization using a tunable vacuum ultraviolet free electron laser. A plethora of sharp vibrational bands features are observed for the first time. Theoretical analysis of these patterns reveals the coexistence of five cubic isomers, including two with chirality. The relative energies of these structures are found to reflect topology-dependent, delocalized multi-center hydrogen-bonding interactions. These results demonstrate that even with a common structural motif, the degree of cooperativity among the hydrogen-bonding network creates a hierarchy of distinct species. The implications of these results on possible metastable forms of ice are considered.
Figure 1
Figure 2
Figure 3
Due to technical limitations, full-text HTML conversion of this manuscript could not be completed. However, the manuscript can be downloaded and accessed as a PDF.