Modeling and simulation of Spectra

Analysis of the spectra of rotation-vibration, theoretical modeling and their simulations is a specificity of spectroscopic activities at LISA. This activity encompasses the development of theoretical models and calculation software to account for the levels of energy, the intensities and profiles of molecular lines, using the tools of quantum mechanics and effective Hamiltonians. These computer softwares are specific to the type of molecular systems written by the researchers to meet the needs of astrophysical and atmospheric Spectra analysis. They take into account the effects for pure rotation, couplings of vibration - rotation, centrifugal distortion, movements of large amplitude, and present effects of hyperfine structure in considered molecules but with the effects of pressure and temperature.


- Codes of vibration - asymmetric and symmetric tops

Our codes of calculations allow to modeling the positions and intensities of the lines for semi-rigid molecules of asymmetric type spin (with three different moments of inertia) or symmetric tops (with two identical moments of inertia [currently et al j Mol.]) Spectrosc, 235, 132 (2006), Perrin et al. j Mol.Spectrosc. (228_(2004) 375)]. Theoretical methods take into account effectively following the case, the hyperfine structure, the interaction between the electron spin and rotation of the molecule, the interactions of vibration - rotation, and when necessary, the effects of large amplitude


- Code BENDING-ROTATION (Coudert et al., j. Mol.) Spec. 251 (2008) 339) is intended for the calculation of the levels of rotation of the molecule of water up to the second triad. It allows the analysis of high resolution data and obtaining potential energy function for the bending mode (the mode n2).


- Code ASYROT (Lauvergnat, Coudert, Klee and Smirnov, j. Mol.) Spec. 256 (2009) 204) has been developed to account for the energy levels of torsional rotation of a molecule with internal asymmetric methyl group rotation partially deuterated CH2D. This code allows analyzing high resolution data of this type of molecules and back to the settings corresponding to the geometry and the potential energy function.


- Several software and associated data have been developed to take into account the effects of collisional interference between transitions in the calculation of the laboratory and atmospheric spectra. These codes are available for CO2 [Lamouroux et al., 111, 2010 JQSRT] CH4 [Tran et al. a, b, JQSRT, 101, 2006;] [Tran et al., JQSRT, 111, 2010] and the A band of O2 [Tran and Hartmann, JGR, 113, 2008] and may be provided to the application.


- Codes BELGI: (Kleiner j. Mol.) Spectrosc, 260 (2010), 1) this codes allow the user to calculate and fit energy levels and transitions of molecules containing a rotor of internal symmetry C3v which can turn relatively to the rest of the molecule. This internal rotation is prevented by a barrier of order 3. The codes are available on the website of Prof. Kisiel or by speaking to the author or by speaking to the author

or by speaking to the author