1. High-Resolution Infrared Spectra of Bicyclo[1.1.1]pentane M.A. Martin a, A. Perry a, T. Masiello b, K. Schwartz a, J.W. Nibler a, A. Weber c, A. Maki d, and T.A. Blake e a.Oregon State University, Corvallis, OR b.California State University, East Bay, CA c.National Institute of Standards & Technology, Gaithersburg, MD d.15012 24 th Ave., SE, Mill Creek, WA 98012 e.Pacific Northwest National Laboratory, Richland, WA

2. Model Views of Propellane and Bicyclo[1.1.1]pentane

5. Why Investigate These Molecules? a. Propellane: a case of very unusual bonding. Bicyclopentane: a close analogue. b. Propellane and Bicyclopentane - simple symmetric tops → D 3h Point Group -good candidates for high-resolution and ab initio studies. c. Synergism between high-resolution and ab initio studies is of interest

8. Resolved K-structure in the 14 (e) Band: The r R K (9) and r R K (10) Stacks

9. Determination of Ground State Parameters Ground state parameters were determined by the method of combination differences from four bands: 17 (a 2  ) at 1220 cm -1 perturbed by 11 (e') at 1232 cm -1 18 (a 2  ) at 832 cm -1 perturbed by 13 (e') at 886 cm -1 14 (e') at 540 cm -1 unperturbed 12 (e') at 1098 cm -1 (partial analysis) These bands furnished a total of 3351 ground state combination differences.

11. Model Views of Propellane and Bicyclo[1.1.1]pentane

12. Upper State Constants for the 14 (e) Band Upper state constants for the 14 (e) band were determined from a combined total of 3529 lines from the p P, p Q, p R, r P, r Q, and r R branches.

14. Summary Ground state parameters for bicyclopentane have been determined from four skeletal rovibration bands using ground state combination differences. The upper state levels of the 14 (e') band were found to be free of perturbations. A full band analysis yielded upper state constants for this band. The results have been compared with those found for propellane and by ab initio calculations. Perturbation analyses of the 17, 18 bands are in progress.