Band contour calculations and l -doubling effects in symmetric top vibration-rotation spectra

摘要: In this lecture I plan to discuss three aspects of our recent work on the analysis high resolution rotation—vibration spectra. The first concerns value using computer-calculated band contours (or computer-simulated spectra) for structure in spectra heavy molecules, situations where is only partially resolved. second origin and importance 1-doubling interactions (and xy axis Coriolis interactions) observed rotational symmetric top molecules. shall demonstrate that, at least certain cases, i-doubling effects produce considerable modifications third subject which wish briefly theoretical treatment complete rovibrational Hamiltonian by means a Van Vleck or contact transformation. This provides best method understanding interactions. also present new results, mainly infrared cylopropane, illustrating work. should like start recalling spectrum CH3F molecule 1460 cm region, illustrated lower half Figure 1. was analysed recently Dr. di Lauro, working my laboratory'; he demonstrated that curious appearance due fact there are two accidentally coincident fundamentals within 10 cm1 each other, interacting through an type perturbation. A1 species parallel band, u2 14600 cm1, E perpendicular 1)5at 14680 cm1. strong interaction between these bands, C2,5(X,Y) constant, produces perturbations true energy levels wavefunctions result J Q branches apparently degrading opposite directions frequency low wings very branch close upper 1 shows pair based model has been correctly allowed its effect positions intensities all lines spectrum. advantage technique computer can be programmed set up diagonalize matrix numerically, without approximation, despite it not possible obtain analytical expressions line intensities. Moreover, computed