LIF Spectrum and Intensity Computing of C¹Π_u→X¹Σ_g⁺ Transitions of ³⁹K₂ Dimer Excited by 4415.6Å Laser Line

The LIF （laser induced fluorescence） spectrum from C~1Пμ→ X^I∑₈⁺ of ³⁹K₂ dimer excited by 4415.6A H_e-C_d⁺ CW laser line is reported. The sample of ³⁹K₂ was produced in heat pipe oven with buffer gas Ar. The LIF spectrum was measured by use of GDR-1000 modal double gratings monochromater. The LIF (laser induced fluorescence) spectrum from C¹Π_u→X¹Σ₈⁺ of ³⁹K₂ dimer excited by 4415.6Å H_e-C_d⁺ CW laser line is reported. The sample of ³⁹K₂ was produced in heat pipe oven with buffer gas Ar. The LIF spectrum was measured by use of GDR-1000 modal double gratings monochromater. The intensity of spectrum was calibrated by tungsten standard lamp. The analysis of spectrum pointed out that LIF spectrum came from the R and P branches of C¹Π_u (v'=0, J'=53)→ X¹Σ_g⁺ (v"=0 -11, J"=52, 54). The rovibration constants of X¹Σ_g⁺ and Te value of C¹Π_u was fitted out by least-squares method. with the formula of the emission spectrum I∝ v⁴R_c²q_v'v" the spectrum intensities of (v'=0, J'=53)-(v"=0-11, J"=52, 54) transitions of ³⁹K₂ was computed by use of RKR potentials. The agreement between the computed values and the experimental one was satisfactory. Further analysis of r-centroid approximation showed that the changing ratio of the dipole transition moment R_e(r) of C¹Π_u→X¹Σ_g⁺ of ³⁹K₂ dimer with internuclear distance r could be deduced by formula \sqrt\frac\left(I_\exp\right)_v^\prime v^\prime \prime\left(I_c a l\right)_v^\prime v^\prime \prime \propto \fracR_e\left(\barr_v^\prime v^\prime \prime\right)R_0=1+\frac\alphaR_0 \barr_v^\prime v^\prime \prime where r_v'v"=/r|v"> was r-centroid computed. The result by use of least-squares fitting was| α/R₀|=-0.157 dcbye/Å in 4.22Å <r< 4.71 Å.