1. FOURIER TRANSFORM MICROWAVE SPECTROSCOPY OF ALKALI METAL HYDROSULFIDES: DETECTION OF KSH P. M. SHERIDAN, M. K. L. BINNS, J. P. YOUNG Department of Chemistry and Biochemistry, Canisius College M. P. BUCCHINO and L. M. ZIURYS Department of Chemistry, Astronomy and Steward Observatory, University of Arizona

2. Metal Hydrosulfides: Previous Work

3. Alkali Metal Hydrosulfides: Previous Work Millimeter-Wave Spectra: −LiSH, 6 LiSH, and LiSD (Janczyk and Ziurys) −NaSH and NaSD (Kagi and Kawaguchi) Bent Molecular Geometries r 0 Structural Parameters Determined No Hyperfine Splitting (Alkali Metal or Deuterium) Resolved KSH and KSD (no previous experimental work)

4. FTMW and Alkali Metal Hydrosulfides Further Investigation of Alkali Metal Hydrosulfides Measure metal hyperfine parameters to investigate metal-ligand bonding character Experimentally detect KSH and KSD, determine geometry, structural parameters and hyperfine constants How? Using FTMW and Discharge Assisted Laser Ablation Build on recent study of LiCCH, NaCCH, KCCH and deuterium isotopologues

5. Fourier Transform Microwave Spectrometer 4 – 60 GHz Cyropumped vacuum chamber Fabry-Perot cavity Supersonic jet 40° relative to optical axis 400 kHz scan increments Ziurys Laboratory FTMW

6. Fourier Transform Microwave Spectrometer Ablation Laser Molecular Jet Cavity Mirror

7. Discharge Assisted Laser Ablation 35 psi backing pressure (open 750  s) Ablation laser: Nd:YAG (532nm, 200 mJ per pulse; 10 Hz rep rate; 1200  s delay) DC discharge 0-500 V (1400  s) 500 - 3000 shots averaged Alkali metal vapor reacted with 0.25% H 2 S or D 2 S in Ar

8. Alkali Metal Rods Al support rod 3 cm long notch, diameter 2 mm smaller Li, Na and K pressed into notch under Ar Only alkali metal portion ablated

9. Initial Search: NaSH Millimeter-wave data of NaSH used to predict frequencies of low J transitions Metal hyperfine constants from alkali metal acetylides used to estimate hyperfine splittings I = 3/2 (Li, Na, K) F = J + I

10. NaSH (X 1 A ʹ ) Spectrum ~ J = 4  3 (K a = 0) F = 3  3 F = 5  5 F = 5  4 6  5 F = 4  3 3  2

11. Lines and Assignments NaSH (X 1 A ʹ ) (K a = 0) J'  J" F'  F" obs  obs -  calc 101.5 11991.708-0.002 2.51.511993.0220.004 0.51.511994.0660.002 434.5 47967.2150.002 2.51.547968.3810.011 3.52.547968.3810.011 4.53.547968.5310.010 5.54.547968.5310.010 2.5 47969.678<0.000 545.5 59957.4180.004 3.52.559958.6420.009 4.53.559958.6420.009 5.54.559958.7380.016 6.55.559958.7380.016 3.5 59959.9420.001 ~

12. Initial Search: KSH Initial Rotational Constants −Scaled M-S bond length from alkali metal sulfides −Used S-H bond length and M-S-H angle from LiSH and NaSH Initially searched 10 MHz centered on J = 1  0 (K a = 0) rotational transition

13. KSH (X 1 A ʹ ) Spectrum J = 7  6 (K a = 0) F = 7  6 6  5 F = 9  8 8  7 Frequency (MHz) ~

14. Lines and Assignments KSH (X 1 A ʹ ) (K a = 0) J'  J" F'  F" obs  obs -  calc 101.5 7118.6780.015 2.51.57119.9940.007 0.51.57121.0470.001 654.53.542715.5690.015 5.54.542715.5690.015 6.55.542715.6330.018 7.56.542715.6330.018 765.54.549833.636-0.010 6.55.549833.636-0.010 7.56.549833.689-0.001 8.57.549833.689-0.001 876.55.556951.150-0.035 7.56.556951.150-0.035 8.57.556951.190-0.028 9.58.556951.190-0.028 ~

15. MSH Rotational Constants Parameter (MHz)NaSH [1]NaSH [2]KSH A292832.7 (4.9)292947.8(7.5)290148 (fixed) B6065.0184(36)6065.0178(43) C5927.7737 (24)5927.7725(62) (B+C)/23646.3021(42)  aa (M) -5.23(39)-5.30(22) rms0.0280.0490.028 [1] Kagi and Kawaguchi, ApJ 491, L129 (1997) [2] Combined fit with previous millimeter-wave data; 3  uncertainties Nuclear spin-rotation could not be reliably determined for either metal

16. KSD Spectrum KSD  J = 8  7 and 7  6 (K a = 0,  F = +1); deuterium hf not resolved J = 7  6 (K a = 0) F 1 = 6  5 5  4 F 1 = 8  7 7  6 Frequency (MHz) I 1 = 3/2 (M) I 2 = 1 (D) F 1 = J + I 1 F = F 1 + I 2

17. Constants MSD [1] Kagi and Kawaguchi, ApJ 491, L129 (1997) [2] Combined fit with previous millimeter-wave data; 3  uncertainties Nuclear spin-rotation could not be reliably determined for either metal Deuterium hf not yet reliably determined Parameter (MHz)NaSD [1]NaSD [2]KSD A150947.8 (5.4)150943.0 (9.9)150136.6 (fixed) B5976.2613 (54)5976.2573 (120) C5730.7996 (15)5730.8002 (108) (B+C)/23545.24204 (45)  aa (M) -5.24 (40)-5.7 (1.3) rms

18. Quantum Calculations LiSH [1]LiSH [2]NaSH [1]NaSH [2,3]KSH [1] M-S (Å)2.1672.1462.5192.4792.845 S-H (Å)1.3431.3531.3431.3541.344 M-S-H (°)93.893.093.893.195.7 [1] CCSD(T)/6-311++G(3df,2pd) Geometric Parameters [2] Janczyk and Ziurys, CPL 365, 514 (2002), r 0 structure [3] Kagi and Kawaguchi, ApJ 491, L129 (1997), r 0 structure Lowest energy geometry for KSH: bent SpeciesKSH [1]KSHKSD [1]KSD (B+C)/2 (MHz)3463.7613646.3021(42)3378.6523545.2420(45)

19. Hyperfine Parameters (MHz) Species 7 Li 23 Na 39 K MF0.41590 (12)-8.4401(15)-7.932397(10) M 35 Cl0.24993(50)-5.6698(60)-5.66583(3) MOH0.2958(15)-7.584(52)-7.454(52) MBH 4 -3.385(31)-4.256(24) MCCH0.378(47)-7.264(20)-6.856(18) MSH -5.23(26)-5.30(22) Nuclear quadrupole coupling small in magnitude and similar to other alkali- containing molecules  consistent with M + L - structure SpeciesMSH LiSH+0.50-0.52+0.02 NaSH+0.61-0.62+0.01 KSH+0.88-0.88+0.01 HF/6-311++G(3df,2pd)//CCSD(T)/6-311++G(3df,2pd) Mulliken Atomic Charges

20. Future Work K a = 1 components of MSH and MSD species LiSH Further investigate ionic/ covalent bonding character of other alkali metal containing molecules Funding : Canisius College & NSF David Ewing: Quantum Calculations