Opening summary -Thesis title: Determination of the potential energy NaLi molecule in the 21Π state based on spectra of polarization labelling spectroscopy.. The molecular constants give
Trang 1SOCIALIST REPUBLIC OF VIETNAM Independence - Freedom – Happiness
INFORMATION SUMMARY ON NEW FINDINGS IN PhD THESIS
1 Opening summary
-Thesis title: Determination of the potential energy NaLi molecule in the
21Π state based on spectra of polarization labelling spectroscopy
- Major: Optics
- Major code: 62.44.01.09
- PhD Student: Nguyen Tien Dung
- Supervisor: 1 Assos Prof Dr Dinh Xuan Khoa
2 Dr Nguyen Huy Bang
- Training institution: Vinh University
2 The new contributions of the thesis
1 Using PLS techniques, spectra of NaLi molecule in 21 states have been observed, for the first time, with rotational solution and 0.1 cm -1
measurement uncertainty A set of 800 spectral lines were identified and used to accurately determine the spectroscopic characteristics of NaLi molecule up to near dissociation limit.
2 Using the method of power expansion of potential, a constant set of 16 molecular constants and lambda doubling coefficient was determined within standard deviation = 0.62 The molecular constants give a simple way to characterized structure of the 21Π state via spectroscopic quantities, such as : bond length, dissociation energy, intensity vibration, and electronic energy On the other hand, the dertermined molecular constants were used to calculate the potential energy RKR method
3 Using the standard classical WKB method, potential energy of the NaLi molecule (that RKR) was determined by the 17 pairs of turning-points and
a minimum corresponding bond length R e = 3.728973 Å Although the RKR does not interpret well the overal experimental data, but it give us the overall picture of the location of the turning point pairs and provide evidence to confirm the potential curve of the 21Π state has a potential barrier (the highest vibrational
Trang 2level v = 16 is higher the limit dissociation).
4 Although experimental spectral data only cover potential domain limited
to R = 7.1 Å but using IPA method, we have identified the potential curve in
21Π state of NaLi molecule up to 16 Å The potential energy is determined accurately in the long-range region allowes determination of dispersion coefficients Cn - is the main parameters to determine "collision" between Na and
Li atoms The IPA potential obtained in the subject potential curve is most accurate to date in 21Π state of NaLi
5 An important result of the study is confirmation of the existence of a small barrier between the two minima of the potential curve in 21Π state of NaLi The behavor of potential barrier is an interesting feature not only by aspect of "singularity" but also an evident to choose the 21Π state as a object to form NaLi molecules from Na and Li atoms based on the photoassociation spectroscopy technique Following thí manner, the cold Na atom in the ground state ( 32S1/2 ) is promoted to the 32P1/2 state and then combines with cold Li atoms in the ground state ( 22S1/2 ) forming cold NaLi molecule in the second barrier Due to the tunneling effect, the cold NaLi molecule will undergo down
to the first minimum of the potential, and then return to the ground electronic state 11Σ+ (steady-state)
Nghe An, 12 th April 2014
Phd Student
Nguyen Tien Dung