10. Sept. 2018: I recently looked into the problem of calculating the electrostatic potential and field of moving charges, and found that the usual derivation in the literature is incorrect. For details see Why the Liénard-Wiechert Retarded Potential is the Result of a Flawed Derivation.

31 Dec. 2009: I modified my 2D- and 3D- collision programs to work for partially inelastic collisions as well (see C/C++ 2D-Collision Code, C/C++ 3D-Collision Code, Fortran 2D-Collision Code, Fortran 3D-Collision Code).
For explanations see the pages Elastic and Inelastic Collision in Two Dimensions and Elastic and Inelastic Collision in Three Dimensions.

10. April 2009: I made now my papers additionally available in PDF format (both this and the original Rich-Text versions are included in the downloads).

9. August 2008: I made another change to my Radiative Transfer Code, splitting the program into two different routines for the source functions and intensities for better flexibility and efficiency.

14. July 2008: I have added an option to select between continuum- (monochromatic) and spectral line scattering to my Radiative Transfer Code. I also changed the initial Neumann series iteration to a direct iteration, as the former led to a slow convergence if absorption is significant (in this respect I also made corresponding changes to my page explaining the corresponding Radiative Transfer Theory).

5. July 2008: I have added the possibility to download the whole site for offline-browsing.

21. June 2008: I have now produced a completely rewritten C/C++ version of my Radiative Transfer Code for a Plane Parallel Multiple Scattering/ Absorbing Atmosphere (note that this requires the kernel function routine mentioned just below (if this is not supplied otherwise)).
The corresponding theory is explained in detail on my page Non-LTE Radiative Transfer of Spectral Lines in a Plane-Parallel Medium.

17. April 2008: I had originally planned to put some of my old radiative transfer codes online, but I found that (for a number of reasons) these are not very suitable for common use, and I have therefore decided to completely rewrite some of them. For a start, I have rewritten the algorithms for the computation of the Kernel Functions for Radiative Transfer in Spectral Lines into C/C++ code.

11. April 2008: Having looked into the issue of 'Inverse Problems' recently, I have decided to develop my own algorithm for this (which should be a lot simpler than many other methods), specifically applied to the case of the Inverse Radiative Transfer Problem. The algorithm itself is listed separately on the page Program Code for Solution (Inversion) of Linear System of Equations.

30. March 2007: I have decided to put some of the source codes of the computer programmes I have written in the past online. More shall be added in the next few weeks and months.

23. Oct. 2006: I added a new page Collisional Relaxation of Gases and Maxwell Velocity Distribution, which explores in more theoretical detail the corresponding points already made on the home page.

31. March 2006: I added a new page regarding my Photoionization Theory for Coherent and Incoherent Light. This is based on the theory developed for the coherent case in my paper Scattering of Radio Waves by High Atomic Rydberg States (Chpt. 2.4) and is essentially a somewhat re-edited version of the treatment I had published on my site under Wave and Particle Theory of Light applied to the Photoelectric Effect. I have removed the incoherent theory there now in order not to complicate things unnecessarily for the discussion there.

22. Feb. 2006: As a kind of complement to the Galactic Redshift page, I added now a page Plasma Theory of 'Gravitational Lensing' which essentially applies the idea that electric fields affect both the frequency and direction of light signals to non-stochastic fields (i.e. fields which are different from zero on average).

17. Dec. 2005: I added a page Plasma Theory of Hubble Redshift of Galaxies to the 'Research' section. This replaces (and expands) some corresponding paragraphs which I had on the Research Home Page as well as on the page Galactic Redshifts and Supernova Lightcurves on my site

9./10 Dec. 2005: I corrected a bug in the collision detection code in my C/C++ 2D-Collision Program (the same for the corresponding Fortran Program). I also changed the code slightly in both cases in order to make it faster (the same for the 3D-versions). Additionally I added a simplified version to the 2D-codes that does not involve the collision detection routine.

17. Oct. 2005: After having this site online for over 4 years now, I decided I should give it a bit of a re-design. For the sake of being able to display longer text documents on smaller monitors, and also for reasons of performance, I have so far shied away from having a highly structured page layout, but I thought it would be justified now at least to add some navigation bars to each page, which should not only enhance functionality, but also give the pages a more coherent look (please note that these changes will only take effect in Javascript enabled browsers, otherwise you will still get more or less the old version; also, with Macs or with the Opera browser, the navigation bars will not be stationary on the screen but scroll with the text; additionally note that at this point I have not included the online versions of my papers in the re-design yet, mainly because they have been converted automatically from Word documents and it would be too much work changing all the HTML consistently; for these I would anyway recommend downloading the Rich-Text file versions as they are better formatted (especially the formulae)).
In the future I shall also give here information about added pages or relevant edits of the existing pages (the most recently added page is Coulomb Collision Cross Section and Coulomb Logarithm which is actually based on a chapter of my Ph.D. thesis).


Thomas Smid (M.Sc. Physics, Ph.D. Astronomy)