the zeeman effect in the optical spectrum of manganese monohydride: mnh. jamie gengler and timothy...
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THE ZEEMAN EFFECT IN THE OPTICAL SPECTRUM OF MANGANESE MONOHYDRIDE: MnH.
Jamie Gengler and Timothy C. Steimle
Department of Chemistry and Biochemistry
Arizona State University
Tempe, AZ 85287-1604
June 18, 2007
Michael Stoll
Molecular Physics
Fritz-Haber-Institut der Max-Planck-Gessellschaft
Faradayweg 4-6, 14195 Berlin, Germany
Motivation.
J.D. Weinstein, R. deCarvalho, T. Guillet, B. Friederich, and J.M. Doyle, Nature (London), 395, 148-150 (1998).
Magnetic trapping of molecules. Ideal candidates have:
1) Unpaired electrons (free-radicals) for nonzero magnetic moment.
2) Large rotational constant for well separated spectral features (diatomic hydrides).
So far, NH and CaH have been successfully trapped.
1) Optical A-X (0,0) transition near 17500 cm-1 is ideal for LIF monitoring of magnetic trap spatial and temporal MnH concentrations.
2) X7+ and A7 states have s = 6 B.
3) Rotational constants of B(X7+) = 5.606 cm-1 and B(A7) = 6.348 cm-1.
4) The X7+ state has much smaller fine-structure parameters of = -0.004 cm-1 and = 0.03 cm-1.
MnH Considerations.
5) The spectra is complicated by hyperfine interactions from both the 55Mn (I = 5/2) and 1H (I = 1/2) nuclei.
10-6 torr
diffusion pump
10-5 torr
diffusion pump
Mn rod (rotated by stepper motor)
20 Hz Nd:YAG
355 nm (10mJ)
CW
Ring-
Dye
Laser
PMT
Lens
Optical filter
Mirror
Molecular beam
20 Hz solenoid pulsed valve
pre-ampGated photon
counter
IEEE computer
board
*
*
*
D/A computer
board
*
*(variable time delay)
Burleigh
wavemeter
RS232 serial
computer board
I2,
etalon
*
H2
300 psi
Helmholtz coils
Laser Induced Fluorescence.
Helmholtz coils (electromagnet)
Polarization of the laser can be rotated by 900 for parallel “||” or
perpendicular “┴” orientation.
Magnetic Fields.
Zeeman Spectra.
1435 GaussExp.
ModelTROT=100 KFWHM=75 MHz
P1(0) Field-Free
17568.1 17568.2 17568.3 17568.4 17568.5 17568.6 17568.7
Laser Wavenumber (cm-1)
Zeeman Spectra.
P1(0) Field-Free
17568.1 17568.2 17568.3 17568.4 17568.5 17568.6 17568.7
Laser Wavenumber (cm-1)
1449 GaussExp.
ModelTROT=100 KFWHM=75 MHz
Quadrupole Magnet
2.3 T
Trap depth: 0.67 K B-1T-1
0 1 2 3 4 5 [T]0 1 2 3 4 5 [T]
Buffer-gas loadingFreezing out of buffer-gas t ~ 5 s
Copper cell
Magnet
3He/4He-Dilution refrigerator for reaching the mK regime
base temperature: 100 mK
Magnetic Trapping.
Magnetic Trapping.
Magnetic Trapping.
Conclusions / Future Work.
1) Molecular beam data closely modeled by simple Zeeman Hamiltonian (RMS ~ 100 MHz, no significant perturbations).
2) Continue refining Zeeman model. Possible inclusion of other branch features and/or anisotropic g-factors.
3) Successful demonstration of magnetically trapping MnH.
4) Determine both elastic and inelastic cross-sections.
5) THANK YOU!!