1. The 68 th International Symposium on Molecular Spectroscopy, June 2013 Fang Wang a, Allan Adam b 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. Stanton Dept. Chem. University of Texas, Austin b Visiting from Chemistry Dept., U. New Bruenswick

2. Noble metals “ Noble” metals actually have a rich and an valuable chemistry

3. Previous Experimental Studies: Theoretical Studies: Bigger basis set and more extensive Spin-orbit

4. What is the current “state-of-the-art” theory for predicting nuclear- electric quadrupole interaction and other “core” properties ? Reasonable agreement    Poor agreement 

5. 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 :

6. eq 0 = elec. field gradient along z-axis.eq 2 = elec. field gradient perp. to z-axis. (also eq 1 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: At. # of bound atom Rot. Par. g-factor Summation over all electronic states

7. 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~200mW Probe beam (~20mW) Laser induced fluorescence(LIF) Pulsed,supersonic beam of RuC

8. Sample Spectra J=3 J=2 A A J=1 M.W. Frequency (MHz) LIF Photon Counts B B

9. A Sample Spectra (cont.) A A 50 khz J=3 J=2 J=1

10. A A Sample Spectra (cont.)

11. Observations and analysis Fit all isotopologues simultaneously using standard reduced mass dependence reduced of B and D. *Need to check this data point/model

12. Results Lan Cheng’s prediction in poor agreement g I =-0.287 + and  - 75 kHz

13. Thank you! Summary 1. ) Surprisingly good agreement between predicted & obs. for ground state eQq 0. 2.) Nuclear spin-rotation parameters more difficult. 3.) A comparison of predicted and measured eQq 2 parameters for 2  is warranted. 4.) How about excited electronic states? 5.) How about magnetic hyperfine parameters?