Atmospheric Chemistry

Michelle FosterDepartment of Chemistry

UMass Boston

5.0m

200nm

5.0m

200nm

Atomic Atomic Force Force MicroscopyMicroscopy

Single Crystal

Powder

Sample Cell for Spectroscopic Studies

to Vacuum Line

IR Window

1 cm

Insulating Substrate

Cooling Bath Coil

Infrared Spectra of the Different Phases of Water

4000 3800 3600 3400 3200 3000 2800

solid

liquid

vapor

Abs

orba

nce

Wavenumber (cm-1)

FLATVAP_B downingwater_B WarrenIce_C

Water Thin Films

½ layer

1 ½ layers

3 layers

Magnesium Oxide Sodium Chloride

Uptake and reaction of gases in liquids

Liquid

Gas Phase

Gas phase diffusion

Bounce off

UptakeDiffusion into bulk

Reaction at interface

Products

Products

Evaporation

Reaction

Undergraduate Researchers:

Kurt van Vloten T.J. Jayasundera Mark D’Agostino Tom DoyleDevon Passno Jennifer Rudberg Sara Yazdi Melinda Furse

Funding:

The Research CorporationPRF-ACSCAS - UMBDepartment of Chemistry

Water Thin Films on Magnesium Oxide

4000 3800 3600 3400 3200 3000 2800 2600

0.005

T = 20oC

Abs

orba

nce

Wavenumber (cm-1)

17 Torr - 5.8 ML 15 Torr - 3.6 ML 11 Torr - 2.5 ML 5 Torr - 1.9 ML 1 Torr - 1.2 ML .1 Torr - 0.7 ML

0 2 4 6 8 10 12 14 16 18 20 22

0

1

2

3

4

5

6

25oC

(H

2O /

sur

face

ato

m)

Pressure (Torr)

adsorption desorption