Search

An overview of the binary collision impact theory of spectral line shapes has been given to provide a unified statistical mechanical approach to line-shape theory, laser theory, nonlinear optics, and transport phenomena in dilute gases. The computation of spectral line profiles corresponding to those obtained from ultra-high-resolution spectral line-shape measurements requires numerical ab initio calculation of scattering amplitudes directly from the underlying dynamics of collisions between radiatively active molecules and their perturbers. The Wigner distribution function-density matrix is utilized to describe the kinetic theory of spectral line shapes and to discuss the various collisional processes that contribute to the kernel of kinetic equations. The influence of features of the potential energy surface on spectral parameters is also discussed, and the importance of comparing experimental line profiles directly with numerically computed line shapes obtained from reliable interaction potentials is emphasized. This contrasts sharply with the universal practice of comparing experimental line widths and shifts using some average or approximate theoretical scattering cross-sections and it contrasts sharply with fitting experimental profiles to some convenient analytical line-shape model; hence the phrase 'a paradigm shift' in the title of this work. [ABSTRACT FROM AUTHOR]

Copyright of Canadian Journal of Physics is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Canadian Journal of Physics is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Canadian Journal of Physics is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)