Numerical Simulations of Diatomic Molecular Optical Spectra

book

English

The first part of the work is dealing with theoretical bases of the calculation solution. The theory is explained from the easiest problems of rotational spectra simulation for polyatomic molecules over the more difficult problems of numerical calculations such as a vibrational spectra or vibrational-rotational spectra to the principles of the electron-vibrational-spectra calculation for the diatomic molecules. Except solution of transition diatomic molecules this work also analyses calculation of absorption coefficients, intensits and also deals with establishment of Höhnel-London factors or transition probabilities. Other part of this work is oriented to the principles of mathematics and numerical methods used in the spectra simulations as convex hull, numerical differentiations of lines, nonlinear regression or deconvolution and convolution. The created program Simul is one of two constituent parts of this work. The electron-vibrational-rotational spectra of diatomic molecules can be simulated by this program and compared with the experimentally measured (there are were tested experimental spectra of the nitrogen molecule and radicals of OH and CN). Except these spectra it can be simulated clear rotational, vibrational, vibrational-rotational and Raman spectra for diatomic molecules. One of the advantage of this program is that it is not limited only to one spectral system that is guaranteed by the projected molecular constant database. This work deals with useful this program in spectroscopy as establishment of rotational temperature and so on the neutral gas temperature both by the simulations and also by Knaus and Caye method, Janin and Eyraurde method or Ornstein-van Wijkov method. Except the rotational temperature there are found out vibrational distribution and vibrational temperature for equilibrium plasma. The molecular spectral systems, which are not in the spectral tables, are possible to identificate by this program or use spectrometers with small distinguishment that is substantially inexpensive. The other constituent part of this work is formed by the program RotSimul that is oriented to simulations of rotational spectra for linear, spherical, prolate symmetric, obligate symmetric and asymmetric rotors. Results of this program were tested on the H3SiCl molecule - prolate symmetric rotor. It also is possible to calculate the moment of inertia for linear, bent, pyramidal, planar and axially symmetric molecules or determine molecular constants with this program. There was also created the menu to analyse experimental spectra by the linear regression, quadratic linear regression, polynomial regression, sum of exponentials, H-spline, nonlinear regession of the Gaussian curve and numerical derivatives (from first to fourth) of the selected line.

numerical simulation, rotational spectrum, electron-vibrational-rotational spectrum, Fourier transformation, deconvolution, spectroscopy, rotational temperature, program Simul, program RotSimul

ŠORMOVÁ, H.

2005

1. 11. 2005

VUTIUM

Brno

80-214-3024-9

Numerical Simulations of Diatomic Molecular Optical Spectra

PhD Thesis

332

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