1. June 18, 200863 rd International Symposium On Molecular Spectroscopy Gas-Phase Rotational Spectrum Of HZnCN (Χ 1 Σ + ) by Fourier Transform Microwave Techniques Ming Sun Aldo Apponi Lucy M. Ziurys Department of Chemistry Steward Observatory University of Arizona

2. June 18, 200863 rd International Symposium On Molecular Spectroscopy Gas phase: solvent Free studies Pure rotational transitions Transient species: radicals/ reaction intermediates Structures, Bond lengths can be precisely determined Electronic Properties Fine-Hyperfine structures Astrochemistry Introduction to Modern FTMW Spectrometer

3. June 18, 200863 rd International Symposium On Molecular Spectroscopy Top View E A B C D  ±  LNA 30 dB PIN Switch ±± 0-50 dB TTL Pulse Sequence High Voltage Solenoid Valve 4-40 GHz   Mixer Computer Coupler Pulse Driver S1S1 S3S3 S4S4 S4S4 S2S2 A/D S3S3 LPF + – Ziurys Group FTMW Spectrometer

4. June 18, 200863 rd International Symposium On Molecular Spectroscopy Mirror sled Linear Actuator 20” mirrors (4 to 40 GHz operation) Complete computer control and tuning NI timing electronics and DAQ Modified FTMW++ (Jens Grabow) Two 8” gate valves for nozzle Radiation/magnetic shield planned 22” cryopump (14000 L/sec Ar) Cryopump Nozzle w/ Dischage setup FTMW Spectrometer

5. June 18, 200863 rd International Symposium On Molecular Spectroscopy Spectroscopy of HZnCN Transition Metal Cyanide MCN studied by Ziurys group Often radicals, including ZnCN No studies of HMCN Production technique 0.5% Zn(CH 3 ) 2 + 0.1% (CN) 2 in 200 Psi Argon 1% D 2 added for DZnCN Brewster and Ziurys, J. Chem. Phys. 117, 4853 (2002). Grotjahn, Brewster and Ziurys, J. Am. Chem. Soc. 124, 5895 (2002). Sheridan and Ziurys, J. Chem. Phys. 118, 6370 (2003).

6. June 18, 200863 rd International Symposium On Molecular Spectroscopy HZnCN (Χ 1 Σ + ) Molecular axis J … I1I1 I2I2 F H = H rot + H Q + H nsr 67 Zn: I = 5/2 14 N: I=1 D: I=1 H: I=1/2 H rot = BJ 2 – DJ 4 H Q = ∆E Q (I,J,F)= H nsr = ∑C I i I i · J

7. June 18, 200863 rd International Symposium On Molecular Spectroscopy

8. June 18, 200863 rd International Symposium On Molecular Spectroscopy

9. June 18, 200863 rd International Symposium On Molecular Spectroscopy

10. June 18, 200863 rd International Symposium On Molecular Spectroscopy Fitted Spectroscopic Constants for Isotopologues of HZnCN (X 1 Σ + ). a Parameter b H 64 ZnCNH 66 ZnCNH 67 ZnCNH 68 ZnCND 64 ZnCND 66 ZnCNH 64 Zn 13 CN B 3859.17616(47)3830.90806(47)3817.337468(283)3804.18983(47)3722.20564(39)3697.66702(40)3817.77804(71) D (KHz) 1.1304(122)1.1161(122)1.1041(111)1.0978(122)1.0076(106)0.9952(110)1.1189(280) eqQ(D) 0.0816(127)0.0755(141) C I (N) (KHz) 1.01(72)0.73(72)1.10(47)0.93(72)1.00(64)0.88(76)0.98(146) eqQ(N) -5.0901(44)-5.0898(44)-5.0896(47)-5.0891(44)-5.0899(37)-5.0915 (42)-5.0892(79) C I (Zn) (KHz) 1.623(265) eqQ(Zn) -104.5792(93) rms 0.00030.00100.00110.00070.00090.00060.0003 a Values in parentheses are 1s errors. b Values in MHz if not specified.

11. June 18, 200863 rd International Symposium On Molecular Spectroscopy Bond lengths for three Zinc species. a HZnCN(Χ 1 Σ + ) b ZnCN(Χ 2 Σ + ) c HZnCH 3 (Χ 1 A 1 ) d r0r0 rsrs r m (1) r0r0 rsrs r0r0 rsrs r HZn (Å)1.4961.4971.4951.521 r ZnC (Å)1.9011.8991.8971.9541.9521.9501.928 r CN (Å)1.1501.1481.146 1.1431.142 Brewster and Ziurys, J. Chem. Phys. 117, 4853 (2002). J. B. Schilling, W. A. Goddard III and J. L. Beauchamp, J. Am. Chem. Soc. 108, 582 (1986). Zn-C bond length: d-π* backbonding: HZnCN vs HZnCH 3 Radical vs Closed-shell: ZnCN vs HZnCN and HZnCH 3 H-Zn bond length: d-π* backbonding causes electron density toward ligand Methyl Steric Hindrance

12. June 18, 200863 rd International Symposium On Molecular Spectroscopy eQq values and related bond lengths of seven species. a HZnCN b HZnCH 3 c ZnCNZnF e CF 3 D CH 3 DDF j eQq(D) (MHz) 0.08 0.17 f 0.19 h 0.35 eQq( 67 Zn) (MHz)-104.57 -109.11 -60 eQq( 14 N) (MHz) -5.09-4.93 b r H-X (Å)1.495 1.5211.091 g 1.086 i 0.923 r Zn-x (Å)1.897 1.928 1.950 d 1.768 r C-N (Å)1.1461.142 d eQq(D) decreases w/ increasing bond length due to “s” orbital character eQq(N) of HZnCN and ZnCN are close eQq( 67 Zn) in both HZnCN and HZnCH 3 are large and indicates huge field gradient across Zn nucleus eQq( 67 Zn) in HZnCN is larger than that in ZnF, which indicates large “p” orbital component

13. June 18, 200863 rd International Symposium On Molecular Spectroscopy Conclusion A relatively large eQq(67Zn) value indicates a large electric field gradient across the zinc nucleus and thus high degree of covalent carbon-metal bonding. Linear Structure of HZnCN was precisely determined. A relatively weak deuterium quadrupole coupling strength indicates a big H-metal distance.

14. June 18, 200863 rd International Symposium On Molecular Spectroscopy Acknowledgments Prof. Lucy Ziurys Dr. Aldo Apponi Rest of Ziurys Group members Engineers and Technicians in ARO NSF NASA