atmospheric chemistry
DESCRIPTION
Atmospheric Chemistry. Michelle Foster Department of Chemistry UMass Boston. Atomic Force Microscopy. Single Crystal. Powder. Sample Cell for Spectroscopic Studies. Infrared Spectra of the Different Phases of Water. ½ layer. 1 ½ layers. 3 layers. Water Thin Films. Magnesium Oxide. - PowerPoint PPT PresentationTRANSCRIPT
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