Structures of Cage, Prism, and Book Isomers of Water Hexamer from Broadband Rotational Spectroscopy

Authors

Cristóbal Pérez
Matt T. Muckle
Daniel P. Zaleski
Nathan A. SeifertFollow
Berhane TemelsoFollow
George C. ShieldsFollow
Zbigniew Kisiel
Brooks H. Pate

Publication Date

5-2012

Description

Theory predicts the water hexamer to be the smallest water cluster with a three-dimensional hydrogen-bonding network as its minimum energy structure. There are several possible low-energy isomers, and calculations with different methods and basis sets assign them different relative stabilities. Previous experimental work has provided evidence for the cage, book, and cyclic isomers, but no experiment has identified multiple coexisting structures. Here, we report that broadband rotational spectroscopy in a pulsed supersonic expansion unambiguously identifies all three isomers; we determined their oxygen framework structures by means of oxygen-18–substituted water (H₂¹⁸O). Relative isomer populations at different expansion conditions establish that the cage isomer is the minimum energy structure. Rotational spectra consistent with predicted heptamer and nonamer structures have also been identified.

Journal

Science

Volume

336

Issue

6083

First Page

897

Last Page

901

Department

Chemistry

Link to Published Version

http://dx.doi.org/10.1126/science.1220574

Recommended Citation

Pérez, Cristóbal; Muckle, Matt T.; Zaleski, Daniel P.; Seifert, Nathan A.; Temelso, Berhane; Shields, George C.; Kisiel, Zbigniew; and Pate, Brooks H.. "Structures of Cage, Prism, and Book Isomers of Water Hexamer from Broadband Rotational Spectroscopy." Science (2012) : 897-901.