1. M. Dehghany, M. Afshari, J. N. Oliaee, N. Moazzen-Ahmadi Department of Physics & Astronomy, University of Calgary, Canada A. R. W. MCKELLAR Steacie Institute for Molecular Sciences, National Research Council of Canada, Ottawa, Canada Infrared spectra of the acetylene-nitrous oxide trimers: The (N 2 O) 2 -C 2 H 2 and (N 2 O) 2 -C 2 D 2

2. a b Qian, et al., Molecular Physics, 91, 689 (1997). Polar and non-polar isomers of (N 2 O) 2 Dehghany, et al., JCP, 130, 044303 (2007). Walker et al., JMS, 251, 153 (2008). a b

3. a b Polar and non-polar isomers of (N 2 O) 2 a b Torsional combination band gives a frequency of 27.1 cm -1 for the out of plane torsional mode. Dehghany, et al., PCCP, 10, 1658 (2008). A second combination band involving the B u intermolecular bend gives a frequency of 42.2 cm -1 for the in-plane geared mode Dehghany, et al., PCCP, in print. The two infrared active dimer vibrations, one due to the in-phase and the other due to the out-of- phase vibrations of the two monomers, from this isomer in the region of the monomer 1 fundamental band have been observed. Berner et al.,JCP, 130, 164305 (2009).

4. Planar near-parallel isomer of N 2 O-C 2 H 2 a b Hu et al., JCP, 95, 1537 (1991). Peebles et al., JPCA, 103, 10813 (1999) Dehghany, et al., CPL, 473, 26 (2009). Torsional combination band gives a frequency of 44.4 cm -1 for the out of plane torsional mode. See talk RA03, Thursday at 9:04.

5. (N 2 O) 2 -C 2 H 2 with C 2 symmetry b a c If the non-polar dimer unit is planar then we expect one band with a- and c-type transitions in the 1 region of the N 2 O monomer.

6. (N 2 O) 2 -C 2 H 2 with C 2 symmetry Q-branchR-branch b a c

7. (N 2 O) 2 -C 2 D 2 with C 2 symmetry Q-branchR-branch b a c

8. b (N 2 O) 2 -C 2 H 2 with C 2 symmetry If the non-polar dimer unit is not planar then we expect an additional band with b-type rotational transitions in the 1 region of the N 2 O monomer. Five coordinates are necessary to characterize the structure, three for the dimer unit and two for acetylene. See talk RA02, Thursday at 8:47.

9. (N 2 O) 2 -C 2 H 2 with C 1 symmetry? Q-branch?

10. (N 2 O) 2 -C 2 D 2 with C 1 symmetry? Q-branch?

11. Thank YOU!