1. Rotational Spectra of Hydrogen-OCS van der Waals Complexes Zhenhong Yu, Kelly Higgins, and William Klemperer Department of Chemistry and Chemical Biology Harvard University Michael McCarthy and Patrick Thaddeus Harvard-Smithsonian Center for Astrophysics

2. paraH 2 orthoH 2 orthoD 2 paraD 2 0 1 0 1 01 13 0 and 2 1 and 5 13 jIT

3. Observed a-type transitions of hydrogen- OCS complexes at K -1 = 0 pH 2 -OCSoH 2 -OCSHD-OCSoD 2 -OCSpD 2 -OCS 1-010595.58610218.27110024.9979517.5599289.155 2-121108.05120385.66419860.56718728.25218345.878 3-231455.67730451.29929332.06427378.21926966.614

4. The spectroscopic constants of hydrogen(j=0)-OCS complexes pH 2 -OCS oD 2 -OCS HD-OCS A B C JJ  JK KK JJ KK 22416.75(103)15971.889(162)12829.367(75) 5995.977(308)5849.626(116)5671.594(74) 4599.888(297)4175.804(109)3846.491(67) 0.06919(252)0.10653(184)0.13153(168) 5.2597(148)2.7398(109)1.1684(97) 24.17(105)6.460(173)3.491(85) 0.017581(135)0.030666(103)0.046989(155) 4.541(150)2.529(56)1.256(34)

5. C O S H H R a b θ β j

6. pH 2 -OCS oH 2 -OCS HD-OCS oD 2 -OCS pD 2 -OCS

7. H = H SS + H eq for oD 2 -OCS d 0 = 3 and eqQ 0 = 223 kHz for oD 2 I = 0I = 2 F = 1 (20.0) 0eqQ 0.153eqQ F = 1 (20.0) -0.175eqQ -0.328eqQ F = 3 (46.7) -0.05eqQ F = 2 (33.3) 0.175eqQ is nonzeroThe off-diagonal matrix element

8. Nuclear hyperfine coupling constants of hydrogen- OCS complexes d a = d 0 or eqQ a = eqQ 0 oH 2 -OCS HD-OCSoD 2 -OCS pD 2 -OCS dada eqQ a  21.2(2) 0.368(4) 0.032(4) 16(2) 0.071(9) 30(2) 0.129(8) 8.4(2) 0.333(8) 0.067(8) j = 1j = 0

9. Structural parameters of the hydrogen(j = 0)-OCS complexes R(Å) pH 2 -OCS HD-OCS oD 2 -OCS He-OCS Ne-OCS Ar-OCS N 2 -OCS (degree) 3.72 3.64 3.59 3.82 3.53 3.70 3.98 109.7 108.7 108.1 113.9 109.6 107.0 110.3

10. Summary The ground state of hydrogen-OCS complex has T- shaped geometry. The internal rotation of hydrogen molecule is decoupled from the molecular axis, leaving the end-over-end rotation of the complex well conserved. Nuclear hyperfine structure indicates that the internal rotation of hydrogen molecule is slightly hindered. The nuclear spin states I = 0 and 2 of orthoD 2 -OCS are strongly coupled through the overall rotation of the complex.