High resolution spectroscopy and potential determination of the(3)~1PI state of NaCs

摘要

The(3)~1PI state of the NaCs molecule was studied by high resolution Fourier-transform spectroscopy.The(3)~1PI->X ~1SIGMA~+ laser induced fluorescence was excited by an Ar~+ ion laser or by a single-mode frequency-doubled cw Nd:YAG laser.The presence of argon buffer gas yielded rich rotational relaxation spectra allowing to enlarge the data set for the(3)~1PI->X ~1SIGMA~+ state term values,as well as to observe A splittings in a wide range of vibrational(v')and rotational(J')quantum numbers.The data field includes about 820 energy levels of(3)~1PI NaCs in the range from v'=0 to 37 and from J'=3 to 190,which corresponds to ca.95% of the potential well depth.Direct fit of the potential energy curve to the level energies is realized using the inverted perturbation approach method;a set of Dunham coefficients is also presented.