1. June 21, 2011 66 th International Symposium on Molecular Spectroscopy Fourier-Transform Microwave Spectroscopy of FeCN (X 4  i ): Confirmation of the Ground Electronic State Lindsay N. Zack, Jie Min, Brent J. Harris, Michael A. Flory, and Lucy M. Ziurys Department of Chemistry and Biochemistry, Department of Astronomy and Steward Observatory, University of Arizona

2. June 21, 2011 66 th International Symposium on Molecular Spectroscopy Importance of Metal Cyanides Metals bonded to CN moiety found in many areas of chemistry Biochemistry (e.g. Vitamin B-12: Co-CN bonds) Pigments (e.g. Prussian Blue: Fe-CN and Fe-NC bonds) Also important in astrophysics Most common metal carriers in interstellar gas (MgNC, MgCN, AlNC, NaCN, KCN identified in several C-rich envelopes) Spectroscopically: Three different structures N M C C N M C N M Alkali-earth/main group M = Ca, Mg, Al, Ga, In (also predicted for early 3d metals) Transition metals M = Cr, Co, Ni, Cu, Zn Alkali metals M = Na, K LINEAR CYANIDE T-SHAPED LINEAR ISOCYANIDE

3. June 21, 2011 66 th International Symposium on Molecular Spectroscopy Previous Work on FeNC/FeCN Laser Fluorescence Spectroscopy (Lie & Dagdigian 2001) Observed  = 7/2′ ←  ″ = 9/2 transition of FeN 12 C and FeN 13 C Proposed 6  ground state; same as FeF and FeCl Theoretical Calculations ( DeYonker et al. 2004; Hirano et al. 2006, 2007; Redondo et al. 2010) Several levels of theory Disagree on lowest energy isomer (FeCN vs. FeNC); agree on 6  ground state A bit confusing !!! Who is correct ?? Rotational Spectroscopy (Flory & Ziurys) Observed several rotational transitions FeCN lowest in energy Proposed 4  i ground state; same as FeH Also measured  = 9/2 ladder of FeNC (X 6  i )

4. June 21, 2011 66 th International Symposium on Molecular Spectroscopy 4i4i  1/23/25/27/2 13/2 11/2 9/2 7/2 J 9/2 7/2 5/2 11/2 9/2 7/2 5/2 3/2 1/2 7/2 5/2 3/2 6i6i  1/23/25/27/2 13/2 11/2 9/2 7/2 J 9/2 7/2 5/2 11/2 9/2 7/2 5/2 3/2 1/2 7/2 5/2 3/2 15/2 13/2 11/2 9/2 1/2 7/2 5/2 3/2 -1/2 Energy Level Diagrams: 4  i vs. 6  i  Lowest transition J = 9/2  7/2Lowest transition J = 11/2  9/2

5. June 21, 2011 66 th International Symposium on Molecular Spectroscopy Lowest transition for 4  i J = 9/2  7/2 ~ 36100 MHz (based on Flory’s rotational constant, B  =7/2 = 4011 MHz) Nitrogen (I = 1) Hyperfine Strongest transitions:  F =  J 5/2

6. June 21, 2011 66 th International Symposium on Molecular Spectroscopy FTMW Spectrometer FFT

7. June 21, 2011 66 th International Symposium on Molecular Spectroscopy Synthesis Fe + 0.25% (CN) 2 in argon Nd/YAG laser 532 nm (2 nd harmonic) DC discharge 1000 V

8. June 21, 2011 66 th International Symposium on Molecular Spectroscopy

9. June 21, 2011 66 th International Symposium on Molecular Spectroscopy Results

10. June 21, 2011 66 th International Symposium on Molecular Spectroscopy Interpretation of h ParameterFeCNCaNC b F /MHz12.48149(93) c /MHz2.0735(14) h /MHz2.55(19) /m -3 2.23 × 10 29 8.47 × 10 29 FeCN (X 4  i ): [core] 8  2 9  2 3  4 10  2 11  2 1  3 4  2 b F ~ 0 (no s orbital contribution) c : 3cos 2  -1 = 2/7 (3d  ), -4/7 (3d  ) small contributions from b and c Scurlock et al. 1994 For FeCN: For CaNC:

11. June 21, 2011 66 th International Symposium on Molecular Spectroscopy Conclusions FeCN has X 4  i ground electronic state –Same as FeH, but different than FeF and FeCl ( 6  i ), i.e. FeCN more covalent than ionic Nitrogen hyperfine parameter, h, determined Other early (Sc, Ti) and intermediate (V, Mn) metal cyanide species need to be studied experimentally. FeCN detectable in space (see talk TF06 later today)

12. June 21, 2011 66 th International Symposium on Molecular Spectroscopy Acknowledgements Prof. Lucy M. Ziurys Dr. Michael A. Flory Ziurys Group NSF NASA