Upload
cody-paul
View
215
Download
0
Embed Size (px)
Citation preview
The 68th International Symposium on Molecular Spectroscopy, June 2013
Fang Wanga, Allan Adamb and Timothy C. Steimle Dept. Chem. & BioChem., Arizona State University, Tempe, AZ,USA
Funded by: DoE-BES
The Rotational Spectrum of RuC by PPMODR
a Currently at JILA
and theoretical predictions
Lan Cheng , and John F. StantonDept. Chem. University of Texas, Austin
b Visiting from Chemistry Dept. , U. New Bruenswick
Noble metals
“Noble” metals actually have a rich and an valuable chemistry
Previous Experimental Studies:
Theoretical Studies:
Bigger basis set and more extensive Spin-orbit
What is the current “state-of-the-art” theory for predicting nuclear-electric quadrupole interaction and other “core” properties ?
Reasonable agreement
Poor agreement
Reduced spherical harmonics
Electric field gradient, R-3 most important near nuclei
Why a comparison nuclear-electric quadrupole interactions is a good test of Relativistic methods:
Electric field gradient:
Quadrupole moment :
eq0 = elec. field gradient along z-axis.eq2 = elec. field gradient perp. to z-axis.
(also eq1 term that mixes electronic states)
nuclear-electric quadrupole interactions
Why a comparison of nuclear-spin rotation is an even a more challenging test of Relativistic methods:
20= -4
nucl i lI
p
e g BZC
m R
2
0
0
ˆ0 L= 4 n xelec
In n
a nC B
E E
ˆ ˆ ˆH I Jeff effns IC . .eff nucl el
I I IC C C At. # of bound atomRot. Par.g-factor
300 = 2 0
4n I N Ba g r nh
Summation over all electronic states
Frequency Sythesizer(0~20GHz)
Rubidium frequency standard
homemade E-field horn antenna(3cmX0.4cm)
Active Frequency multiplier 4X or 2X
Magnetic sheild box
FWMH: 70kHz with<<1mW power
PPMODR(Experimental)
Microwave Radiation Source
Pump beam~200mWProbe beam (~20mW)
Laser induced fluorescence(LIF)
Pulsed ,supersonic beam of RuC
Sample Spectra
J=3
J=2
A
A
J=1
M.W. Frequency (MHz)
LIF
Photo
n C
ou
nts
BB
Sample Spectra (cont.)
A
A
50 khz
J=3
J=2
J=1
A
A
Sample Spectra (cont.)
Observations and analysis
Fit all isotopologues simultaneously using standard reduced mass dependence reduced of B and D.
*Need to check this data point/model
Results
Lan Cheng’s prediction in poor agreement
gI=-0.287
+
2
0
0
ˆ0 L= 4 n xelec
In n
a nC B
E E
300 = 2 0
4n I N Ba g r nh
and - 75 kHz
Thank you!
Summary
1. ) Surprisingly good agreement between predicted & obs. for ground state eQq0 .
2.) Nuclear spin-rotation parameters more difficult.
3.) A comparison of predicted and measured eQq2 parameters for 2 is warranted.
4.) How about excited electronic states?
5.) How about magnetic hyperfine parameters?