The 68 th International Symposium on Molecular Spectroscopy, June 2013 Fang Wang a, Allan Adam b and...

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?