Thong tin luan an tieng anh bang corrected 17 04 2014

SOCIALIST 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
1
2 Π 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 Re = 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


level 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 2 1Π 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 2 1Π 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, 12th April 2014
Phd Student

Nguyen Tien Dung