Analysis of the FASSST rotational spectrum of S(CN) 2 Zbigniew Kisiel, Orest Dorosh Institute of Physics, Polish Academy of Sciences Ivan R. Medvedev, Marcus Behnke, Frank C. De Lucia, Eric Herbst, Manfred Winnewisser Department of Physics, The Ohio State University 60th OSU International Symposium on Molecular Spectroscopy FC05

The r m  geometry of S(CN) 2 : Demaison et al. : Demaison et al. : J.Mol.Struct. 376, 399 (1996) (7) o 98.38(6) o 1.699(1) Å 1.159(1) Å

Previous studies by rotational spectroscopy: Arnold, Dreizler, Rudolph: Arnold, Dreizler, Rudolph: Z.Naturforsch. 19a, 1428 (1964) cm-wave rotational spectrum of parent isotopomer assigned and dipole moment measured,  b = 3.01(1) D Pierce & Nelson: Pierce & Nelson: JCP 43, 3423 (1965) ground state A,B,C for the parent + 34 S, 13 C, 15 N isotopomers, and for v 4 =1 satellite in parent Jemson & Gerry: Jemson & Gerry: JMS 124, 481 (1987) ground state measurements extended (in cmw region) and constants up to sextic determined

Lowest energy vibrational states in S(CN) 2  4 = 122 cm - 1 A 1  7 = 328  8 = 366  9 = 372  3 = 496 Frequencies are unscaled B3LYP/6-31G(d,p) Other modes (cm - 1 ): obs.calc.  A B B A 1 B1B1 B2B2 A2A2 A1A1

AgCN in CS 2 + SCl 2  reacted for  1 hour  CS 2 distilled off S(CN) 2 : yellowish crystals kept in dry ice Preparation of S(CN) 2 and FASSST spectrum FASSST FASSST spectrum recorded over GHz using three different mmw sources Sample flow through cell eliminating volatile impurities Spectrum recorded at room temperature and at 190 o C

Analysis carried out using the AABS software package Spectra and predictions displayed alongside with two previewing programs Graphical assignment and automated transfer of frequencies and quantum numbers to datafiles Fitting and predictions with ASFIT/ASROT and with H.M.Pickett’s SPFIT/SPCAT Package is expected to be suitable for analysis of other types of broadband, rotationally resolved spectra – tests are encouraged AABS = A ssignment and A nalysis of B roadband S pectra available on the PROSPE webpage:

Vibrational satellites of characteristic R-type transitions 32 0,32  31 1, ,32  31 0,31   4 =

Synthetic overview of the ground state dataset Symbol size is proportional to: ( obs - calc )/  Red symbols denote ( obs - calc ) > 3 

Aspects of FASSST calibration… Absolute calibration, FASSST vs PLL (Medvedev et al., JMS 228, 314,2004) AABS Linewidths from automatic peakfinder in AABS

Linewidths in FASSST spectra (FWHH /MHz) Spectra of two different molecules recorded ca 1 year apart

Constants for the ground state of 32 S(CN) 2 + octics * 0.96f scaled B3LYP/6-31G(d,p), calculation: * GAMESSGAMESSFCONVFCONVVIBCAVIBCA  fit /kHz Up-scanned only: 72.9 Up/down average:53.3

Changes in constants on excitation of the 4 bending mode  quartics  octics sextics  A,B,C  KK   C  JK

Lowest energy vibrational states in S(CN) 2  4 = 122 cm - 1 A 1  7 = 328  8 = 366  9 = 372  3 = 496 Frequencies are unscaled B3LYP/6-31G(d,p) Other modes (cm - 1 ): obs.calc.  A B B A 1 B1B1 B2B2 A2A2 A1A1

Statistical weights in rotational transitions of S(CN) 2 Successive R-type transitions pairs for same J and K - 1 =2  1 and K - 1 =1  2 2:1 weights are due to symmetry equivalent 14 N nuclei with I =1. AABS The AABS package requires only a single keystroke to jump between successive regions of the spectrum. Alternatively a switch to the Loomis-Wood display can be made…

Loomis-Wood plot for S(CN) 2 illustrating statistical weights

Assignment of vibrational satellites: Working Weight Inertial defect (uA 2 ) Mode label obs. calc. n  calc  gs (2) (4) A 1 N (4) B 1 NN (2) B 2 NNN+ 1.03(7) A 2 L+ 0.97(4) A 1 Working Weight Inertial defect (uA 2 ) Mode label obs. calc. n  calc  gs (2) (4) A 1 N (4) B 1 NN (2) B 2 NNN+ 1.03(7) A 2 L+ 0.97(4) A 1 Weight = statistical weights relative to the ground state, + stands for unchanged weights, - denotes reversed weights

34 S(CN) 2

Conclusions:Conclusions: Spectroscopic constants determined for the ground state and nine different vibrational excited states First excited states of five different normal modes measured Extensive results also for the 34 S isotopomer and some for 13 C isotopomer AABS Highly efficient AABS software package developed in response to the need to process and manage data for many states simultaneously No signs of quantum monodromy – barrier to linearity very high (but have you seen talk TH07 on NCNCS ? ) To do: Analysis of interstate interactions ?