At the University of Colorado, I have helped pioneer a new technique to probe depositional ice nucleation onto internally mixed ammonium sulfate/palmitic acid particles, namely optical microscopy coupled with Raman microscopy. The deliquescence and efflorescence phase transitions of the mixed particles were first studied to gain insight into whether the particles are likely to be liquid or solid in the tropical tropopause region. The ice nucleating ability of the particles was then measured under typical upper tropospheric conditions. It was found that coating the particles with insoluble palmitic acid had little effect on the deliquescence, efflorescence or ice nucleating ability of ammonium sulfate. Additional experiments involving Raman mapping provided new insights into how the composition and morphology of mixed particles impact their ability to nucleate ice. Future research will be devoted to studying other types of particles using the Raman system.
aerosols, ice nucleation, cloud formation, water uptake
CHEM 1114 - Laboratory in General Chemistry 1
Lab. Intended for first-semester students whose academic plans require advanced work in chemistry. Instruction in experimental techniques which coordinate with lecture topics in CHEM 1113. Department enforced prerequisites: one year high school chemistry or CHEM 1021 (min grade C-); high school math through pre-calculus. Not recommended for students with grades below B- in CHEM 1021. Department enforced corequisites: CHEM 1113. Not open to engineering students with exception of EPEN majors. Credit not granted for this course and CHEM 1401 or CHEM 1221.