1. An Analysis of the 3 band of HTO aided by the Partridge and Schwenke PES Modou Tine and Laurent H. Coudert Laboratoire Inter-Universitaire des Systèmes Atmosphériques Créteil, France

2. Why? Only the ground state 1 and the 1 band 2 have been studied under high-resolution. HTO is an unstable species found in accidental releases from nuclear reactor. Half life is 12.3 years. 1 Helminger et al., Phys. Rev. A 10, 1072 (1974) 2 Cope et al., J. Molec. Spectrosc. 127, 464 (1988)

3. Overview 2. The experimental spectrum of the 3 band. 1. The vibrational modes and vibrational states. 3. The first analysis of the 3 band. 4. Energy level calculation with Partridge and Schwenkee’s PES 1 1 Partridge and Schwenkee, JCP 106, 4618 (1997) 5. Taking into account the perturbation.

4. The Vibrational Modes

5. The Vibrational States

6. The infrared spectrum It was recorded in 1972 by Guy Steenbeckeliers and Andre Fayt at Louvain University in Belgium. They used an Ebert- Fastie grating spectrometer with a 0.035 cm  1 resolution.

7. The HTO sample cell A 7 inch long cell was filled with a mixture of T 2 O and H 2 O.

8. The experimental spectrum 3 22  3 21 5 23  5 24 a- and b-type transitions

9. The first analysis It was carried out using a Watson-type Hamiltonian for the ground and (001) vibrational states. Rotational and distortion constants in the ground state were set to the values of Helminger et al. 1 1 Helminger et al., Phys. Rev. A 10, 1072 (1974)

10. First analysis: The obs.  cal. table 48 lines were excluded because there is a perturbation. 533 lines were assigned. The RMS deviation is 0.018 cm  1

11. The effects of the perturbation 8 levels of the (001) state are very perturbed.

12. Using the Partridge and Schwenke PES We can obtain vibrational states

13. Accounting for the perturbation The data for the (001) state and the calculated energy levels for the (110) state will be fit together.

14. Final analysis: The obs.  cal. table 520 transitions fitted. The RMS deviation is 0.014 cm  1 Only 13 transitions were excluded.

15. Final analysis: The perturbed levels RMS deviation for the (110) state is 0.16 cm  1

16. Final analysis: The constants in cm  1