an analysis of the 3 band of hto aided by the partridge and schwenke pes modou tine and laurent h....
TRANSCRIPT
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
Why?
•Only the ground state1 and the 1 band2 have been studied under high-resolution.
•HTO is an unstable species found in accidental releases from nuclear reactor. Half life is 12.3 years.
1Helminger et al., Phys. Rev. A 10, 1072 (1974)2Cope et al., J. Molec. Spectrosc. 127, 464 (1988)
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 PES1
1Partridge and Schwenkee, JCP 106, 4618 (1997)
5. Taking into account the perturbation.
Th
e V
ibra
tion
al M
odes
Th
e V
ibra
tion
al S
tate
s
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 cm1 resolution.
The HTO sample cell
A 7 inch long cell was
filled with a mixture of
T2O and H2O.
The experimental spectrum
322321523524
a- and b-type transitions
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
1Helminger et al., Phys. Rev. A 10, 1072 (1974)
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 cm1
The effects of the perturbation
8 levels of the (001) state are very perturbed.
Using the Partridge and Schwenke PES
We can obtainvibrational states
Accounting for the perturbation
The data for the (001) state and the calculated energylevels for the (110) state will be fit together.
Final analysis: The obs. cal. table
520 transitions fitted. The RMS deviation is 0.014 cm1
Only 13 transitions were excluded.
Final analysis: The perturbed levels
RMS deviation for the (110) state is 0.16 cm1
Final analysis: The constants in cm1