Hydrogen Bonding in the Prism Face of Ice Ih a Study via Sum Frequency Generation Vibrational Spectroscopy.
Abstract: The prism face of single crystal ice Ih has been studied using sum
frequency vibrational spectroscopy focusing on identification of resonances in the
hydrogen-bonded region. Several modes have been observed at about 3400 cm-1; each mode is
both polarization and orientation dependent. The polarization capabilities of sum frequency
generation (SFG) are used in conjunction with the crys... read moretal orientation to characterize three
vibrational modes. These modes are assigned to three-coordinated water molecules in the
top-half bilayer having different bonding and orientation motifs. Such mode identification
is only possible with the production and use of single crystal ice of very low defect
density and of size appropriate for examination using the SFG technique. Production of
single crystal ice is often trivialized in the literature. But in reality, large single
crystals are very difficult to produce. Design and construction of an apparatus and
protocol that can produce large single crystals of ice truly advances the state of the art.
An apparatus utilizing the Bridgeman-Stockbarger method of single crystal growth was
designed, constructed and optimized for the growth of ice. This design features a software
implemented (LabVIEW) Proportional-Integral-Differential (PID) feedback temperature control
algorithm. The temperature at the growth interface was controlled to within +/-0.002K even
though room temperature variation was ca. +/-2K. Since the measurement must occur at
cryogenic temperature (ca. 130K), the design and construction of a cell that can enclose
and isolate the ice sample from ambient conditions is also of critical importance. An air
tight, all glass design was chosen that incorporates two fused IR quartz windows to allow
for visible and mid-IR transmittance, an oxygen free copper heat sink and a unique ice
mounting scheme. The thermal design of the heat sink and ice mount are critical for
reaching cryogenic temperatures and insuring the ice sample remains attached to the heat
sink as the temperature is lowered.
Thesis (Ph.D.)--Tufts University, 2013.
Submitted to the Dept. of Chemistry.
Advisor: Mary Shultz.
Committee: Mary Shultz, Jonathan Kenny, Roger Tobin, and Sergiy Kryatov.
Keywords: Chemistry, and Physical chemistry.read less