1. FTIR EMISSION SPECTROSCOPY AND AB INITIO STUDY OF THE TRANSIENT BO AND HBO MOLECULES 65 th Ohio State University International Symposium on Molecular Spectroscopy Gang Li, Rob Hargreaves and Peter Bernath The University of York, UK

2. Outline  Introduction  Previous work and motivation  Experimental setup and results  Ab initio calculations using Molpro  Future work  Summary  Acknowledgements

3. Introduction – Boron chemistry Boron propellant Fuel cell & hydrogen storage Future nuclear power Formation of boron in universe Boron Stellar nebulae Boron fission reaction Honda hybrid car Spacecraft with boron propellant

4. BO - Previous work and motivation  A 2 Π – X 2 Σ + and B 2 Σ + – X 2 Σ + of BO were first identified by Mulliken in 1925.  High resolution measurements on these electronic band systems were carried out by Coxon et al. and Mélen et al.  In 1985 the microwave spectrum of BO was recorded by Tanimoto et al.  More recently, an infrared measurement of the BO fundamental band was performed by Stancu et al. using diode laser spectroscopy.

5. BO - Previous work and motivation  The microwave and diode laser measurements only probed the v = 0 and v = 1 vibrational levels of the ground state of BO.  In the infrared laser study, only 19 lines and 12 lines for the fundamental bands of 11 B 16 O and 10 B 16 O were observed, respectively, and no hot bands were detected.  The Fourier transform measurements presented here contained the fundamental bands of both isotopic species, 11 BO and 10 BO, along with one hot band of the main isotopologue 11 BO with 95, 72 and 64 lines, respectively.

6. BO - Previous work and motivation  In the previous infrared work, the O + BCl 3 reaction was used to synthesize BO, which required very specific experimental conditions and relatively low concentrations of BO were obtained.  We have adopted a different method to produce the molecules in this work which led to a higher concentration of BO more suitable for infrared emission spectroscopy.

7. Experimental setup The emission source that combines DC discharge and a high temperature furnace. B2O3B2O3

8. Modelling of solar nebula DC discharge 3 kV, 50~333 mA Lauretta and Lodders in 1996 Modelling of solar nebula, suggested that HBO, BO, HOBO might form at high temperature. H - B - O HBO v 3 band at 1300 o C BO was found at 1400 o C with DC discharge

9. BO spectrum Fourier transform emission spectrum of BO with DC discharge (3 kV, 333 mA).

10. Data analysis  Calibrated with the NIST CO line list & fitted with a Voigt lineshape function using WSpectra program.  A Loomis-Wood program was used to identify the observed bands.  J values assigned using lower state combination differences.  A combined least-squares fit with the microwave data and the diode laser data was performed, and spectroscopic constants were obtained.

11. Results for BO (a) Stancu et al. (2004); (b) Melen et al. (1985); (c) Tanimoto et al. (1986)

12. Results for BO (a)Stancu et al. (2004); (b) Melen et al. (1985); (c) Coxon et al. (1986)

13. HBO-Previous work and motivation  Infrared diode laser detection of HBO v 3 band by Kawashima 1986 – only 23 lines  HBO microwave spectrum by Kawashima in 1987  Improved HBO microwave spectrum by Kawashima in 1989  Modelling of solar nebula, suggested that HBO, BO, HOBO might form at high temperature. Lauretta and Lodders in 1996

14. HBO v 1 band H - B - O

15. HBO v 3 band H - B - O

16. Data analysis  Similar procedures for analysing BO spectrum were used.  Fundamental bands and 23 hot bands were then identified.  Combined data from Kawashima microwave data and performed least squares fit.  Preliminary molecular constants were obtained.  Assignment of more hot bands is in progress.

17. Preliminary results  Assignments of the 23 HBO hot bands need the assistance of ab initio calculation results.  BeF 2 hot bands were analysed with the help of ab initio calculations. Calculated B e was in remarkably good agreement with experiment.[1] Molecular constants of HBO molecule [1] The vibration-rotation emission spectrum of hot BeF 2. Shanshan Yu et al. JCP 123, 134303 (2005)  10 6

18. Potential energy surface (PES) using Molpro  An accurate potential energy surface was calculated at MRCI + ACVnZ (n=T,Q) levels.  24*24*11 grid  Vibrational calculation will be performed using this surface. Calculated HBO potential energy surface (PES) at linear geometry using Molpro with MRCI method and aug-cc-pVQZ basis set.

19. Future work  Similar systems: boron sulfide (BS), boron hydrosulfide (HBS), boron hydrofluoride (HBF).  Finish the vibrational calculation and assignments of HBO.  Try to assign the possible HOBO band.

20. Summary The high-resolution infrared emission spectra of BO and HBO were recorded. Molecular parameters were obtained for BO and HBO. An accurate potential energy surface was calculated for HBO.

21. Acknowledgements Prof. Peter Bernath Rob Hargreaves Dr Jin-Guo Wang Hui Li and Prof. Leroy NSCCS-Magellan Other members in our group Thank you for listening! Wild Fund

22. Questions?