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Near-Infrared Spectroscopy of Interstellar and Planetary Ice Analogs
Amanda M. Cook
Dr. Perry A. Gerakines
Research Funded by a grant from the NSF REU program
Where are ices detected?
• Interstellar CloudsInterstellar Clouds
• CO: Triton, Pluto, CometsCO: Triton, Pluto, Comets
• NHNH33: Miranda, Charon: Miranda, Charon
• CHCH44: Triton, Pluto, Kuiper Belt Objects, : Triton, Pluto, Kuiper Belt Objects,
CometsComets
Spectroscopy• Bending Modes
• Stretching Modes
• Resonance
O
H H
Combined Near-IR and Mid-IR Spectra of N2+CH4
10000 8000 6000 4000 2000
0.0
0.5
1.0
1.5
Abs
orba
nce
Wavenumber (cm-1)
Experimental Set-up
Turbo-pump
Helium CoolingSystem
Gas Bulb
UV lamp
Infrared Beam from Spectrometer
Sample Chamber
NH3+CO Photolysis Products
10000 8000 6000 4000 2000-0.5
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
5.0
5.5
6.0
Unphotolyzed Sample
Photolyzed Sample
Ab
so
rba
nce
Wavenumber (cm-1)
A Closer Look…
7000 6500 6000 5500 5000 4500 4000-0.2
0.0
Photolyzed Sample
Unphotolyzed Sample
Abs
orba
nce
Wavenumber (cm-1)
NH3+CO Photolysis Product
4760 4740 4720 4700 4680 4660 4640-0.05
-0.04
-0.03
-0.02
48 hr UV Deposit (30K) 48 hr UV Deposit (11K) 44 hr UV Deposit (11K) 36 hr UV Deposit (11K) Unphotolyzed Deposit
Abs
orba
nce
Wavenumbers (cm -1)
Quirico and Schmitt (1997)
5400 5200 5000 4800 46000.0
0.2
Pure CO2 Deposit
Abs
orba
nce
Wavenumber (cm-1)
Pure CO2 Deposit Pure Ethylene
Identifying the Feature
Triton Spectrum
Cruikshank et al. (1993)
N2+CH4 Photolysis Products
10000 8000 6000 4000 2000
0.0
0.5
1.0
1.5
2.0
Unphotolyzed Sample
Photolyzed Sample
Absorb
ance
Wavenumber (cm-1)