Download presentation
Presentation is loading. Please wait.
Published byWinifred Fields Modified over 9 years ago
1
CALIFORNIA INSTITUTE OF TECHNOLOGY 68th International Symposium on Molecular Spectroscopy - June 19, 2013 A LOW-COST CHIRPED-PULSE FOURIER TRANSFORM MICROWAVE SPECTROMETER FOR UNDERGRADUATE PHYSICAL CHEMISTRY LAB Brandon Carroll Ian A. Finneran Geoffrey A. Blake
2
STARK SPECTROMETER Hewlett-Packard Journal
3
STARK SPECTROMETER Hewlett-Packard Journal June1971
4
INTRODUCTION
5
ROTATIONAL SPECTRUM OF OCS
7
J = 1 J = 0 F = 3/2 F = 5/2 F = 3/2 F = 1/2 F = 5/2 F = 3/2 eqQ = 0eqQ > 0eqQ < 0 -0.25 eqQ -0.05 eqQ +0.20 eqQ -0.25 eqQ -0.05 eqQ +0.20 eqQ
8
ROTATIONAL SPECTRUM OF OCS J = 1 J = 0 F = 3/2 F = 5/2 F = 3/2 F = 1/2 F = 5/2 F = 3/2 eqQ = 0eqQ > 0eqQ < 0 -0.25 eqQ -0.05 eqQ +0.20 eqQ -0.25 eqQ -0.05 eqQ +0.20 eqQ
9
ROTATIONAL SPECTRUM OF OCS J = 1 J = 0 F = 3/2 F = 5/2 F = 3/2 F = 1/2 F = 5/2 F = 3/2 eqQ = 0eqQ > 0eqQ < 0 -0.25 eqQ -0.05 eqQ +0.20 eqQ -0.25 eqQ -0.05 eqQ +0.20 eqQ
10
CP-FTMW 30 seconds
11
CP-FTMW ISMS 2013 WH07
12
CP-FTMW ISMS 2013 WH07
13
CP-FTMW
14
CP gives all the same information –Cover 11 GHz – 12 GHz –Detect 16 O 12 C 32 S, 16 O 12 C 34 S, 16 O 13 C 32 S, 16 O 12 C 33 S Time domain spectroscopy Coherence Simple analysis Strong links to other experiments (NMR, EPR) Can be done inexpensively UNDERGRADUATE CP-FTMW
15
CP gives all the same information –Cover 11 GHz – 12 GHz –Detect 16 O 12 C 32 S, 16 O 12 C 34 S, 16 O 13 C 32 S, 16 O 12 C 33 S Time domain spectroscopy Coherence Simple analysis Strong links to other experiments (NMR, EPR) Can be done inexpensively UNDERGRADUATE CP-FTMW
16
INSTRUMENT DIAGRAM X Band Waveguide Stark cell SPST Switch
17
INSTRUMENT DIAGRAM X Band Waveguide Stark cell SPST Switch
18
PARTS
19
Tunable 11.2 – 13.1 GHz Phase moderately stable $ 150 PLL VCO
20
6 -18 GHz $200 - $1300 Enclosed, simple Reasonable noise figure, power Robust RF AMPLIFIERS AND MIXERS
21
Simple programming Moderate timing jitter (~100ns) Controls AD9914 automatically Multiple output channels TIMING I/O
22
Linear frequency ramps 0 – 2 GHz Phase stable Tunable, stepped LO source $ 600 DDS
23
Linear frequency ramps 0 – 2 GHz Phase stable Tunable, stepped LO source $ 600 DDS
25
200 MHz Bandwidth 1 GS/s > 1kHz acquisition Onboard FFT, including windowing 60,000 Waveform memory $1575 OSCILLOSCOPE
26
SPECTROMETER
27
16 O 12 C 32 S 50,000 averages
28
16 O 12 C 34 S 100,000 averages
29
16 O 13 C 32 S 500,000 averages
30
16 O 12 C 33 S 1 million averages
31
16 O 12 C 33 S 1 million averages 15 minutes!
32
16 O 12 C 32 S COHERENCE
33
PARTS LIST
34
Design is extremely versatile Can be adapted to multiple experimental designs Applicable to numerous molecular systems Research applications Lots more to come Instructions available at http://www.gps.caltech.edu/~gab/resources. html CONCLUSIONS
35
ACKNOWLEDGEMENTS Blake Lab: -Marco Allodi -Brett McGuire -Sergio Ioppolo -Xander de Vries -Jacob Good - Nate Crockett -Masha Klescheva -Coco Zhang -Dana Anderson -Katherine Kaufman -Alex Lockwood Caltech: -Daniel Thomas -Jack Beauchamp -Dan Weitekamp
Similar presentations
© 2025 SlidePlayer.com. Inc.
All rights reserved.