1. Microwave spectroscopy of the heavy-atom carbene analog HSiI and DSiI Lu Kang Southern Polytechnic State University Marietta, GA Mohammed A. Gharaibeh and Dennis J. Clouthier University of Kentucky, Lexington, KY Stewart E. Novick Wesleyan University, Middletown, CT

2. Dennis Clouthier (pronounced Clue-chay) Pete Pringle (pronounced Pringle) & Lu Kang Jim Cederberg, St. Olaf College Lu is at St. Olaf learning to use Jim’s MBER (originally Norman Ramsey’s)

3. H 3 SiI in a methanol/dry ice bath held between -40 and -50 C, P ~ 5 torr 5 torr H 3 SiI in 2 atm of Ne, discharge of -1000 V immediately following supersonic expansion to produce HSiI (or DSiI if we start with D 3 SiI)

4. 2/3 Spectroscopic constants of HSiI as measured by FTMW spectroscopy

5. The r 0 structure of HSiI 1.5405 A 92.68 o 2.4614 A

6. This workClouthier et al a r 0 (H – Si)1.5405(16) Å1.534(1) Å r 0 (Si – I)2.46143(9) Å2.463(1) Å θ 0 (HSiI)92.68(6)°92.4(1)° a. D.J. Clouthier, W.W. Harper, C.M. Klusek, T.C. Smith, J. Chem. Phys. 109, 7827 (1998), jet-cooled pulsed-discharge

7. HSiCl a HGeCl b HGeBr c HSiI d Bond angle 95 o 95.3 o 94.1 o 92.7 o (X bb -X cc ) X aa -1.185 e -1.025 e -0.965-0.914 a. W. Lin, S. E. Novick, M. Fukushima, W. Jäger, J. Phys. Chem. A 106, 7703 (2002), D.A. Hostutler, N. Ndiege, D.J. Clouthier, S.W. Pauls, J. Chem. Phys. 115, 5485 (2001) b. W. Lin, L. Kang, S.E. Novick, J. Mol. Spectrosc. 230, 93 (2005) c. L. Kang, F. Sunahori, A.J. Minei, D.J. Clouthier, S.E. Novick, J. Chem. Phys. 130, 24317 (2009) d. This work e. B3LYP/aug-cc-pvqz

8. b a c χ aa =-795.744 MHz χ bb =+833.330 MHz χ cc =-37.586 MHz Extended Townes-Dailey analysis of the quadrupole tensor χ 0 = +2292.712 MHz, 127 I, 5p electron. Gordy & Cooke has +292.71 MHz, a typo. HSiI: n a = 1.53, n b = 2.00, n c =1.75 {HGeBr: n a = 1.58, n b = 2.00, n c = 1.80}