Cosmos, origin

There are many technical details involved in SCRF calculations, many of which the user can control. Readers of this book are advised to use the default values as much as possible unless they have carefully examined the original literature and tested their modifications. PCM methods are generally more accurate than the Onsager and COSMO methods. 

Values calculated based on original and interpolated Abraham descriptors. Values in brackets are calculated based on Abraham parameters regressed from COSMO a-moments [65]. 

At around this time, there was much scientific debate about the theory of the origin of species proposed by Charles Darwin (1809-1882), a theory which was to change the world. Darwin himself was very cautious about making statements on biogenesis. It was still too early to answer such questions, because neither results from the science of cell biology nor an extensive knowledge of our planet, the solar system and the cosmos were available. 

Zubay G (2000) Origins of Life on the Earth and in the Cosmos 2nd Ed. Academic Press, San Diego, New York... 

The Universe has no centre. No privileged place can be taken for the origin of our coordinate systems, for the centre of the world. The last revolution is the most radical of all, for it touches the very stuff of the cosmos, its very materiality. With all the assurance of its well-oiled atomic mechanics, humankind declares Matter that shines and radiates is a mere froth on the surface of dark matter and quintessence. ... 

Almost three millennia separate this genealogy of the gods from the modem idea of the expanding cosmos and the stellar origins of human matter, summed up so concisely in the two statements ... 

Kato, R. and Gmehling, J., Systems with ionic liquids measurements of VLE and data and prediction of their thermodynamic behavior using original UNIFAC, mod. UNIFAC(Do) and COSMO-RS(Ol), /. Chem. Thermodyn., 37, 603, 2005. 

In addition to the processes of stellar nucleosynthesis, there are two other ways in which isotopes are produced. One is radioactive decay. Many of the nuclides produced by explosive nucleosynthesis are unstable and decay to stable nuclei with timescales ranging from a fraction of a second to billions of years. Those with very short half-lives decayed completely into their stable daughter isotopes before any evidence of their existence was recorded in objects from our solar system. However, radioactive nuclei from stellar nucleosynthesis that have half-lives of >100 000 years left a record in solar system materials. For those with half-lives of more than 50 million years some of the original nuclei from the earliest epoch are still present in the solar system today. The ultimate fate of all radioactive nuclides is to decay to their stable daughter nuclides. Thus, the only real distinction between isotopes produced by stellar nucleosynthesis and those produced by decay of radioactive nuclides produced by stellar nucleosynthesis is the time scale of their decay. We choose to make a distinction, however, because radioactive nuclides are extremely useful to cosmo-chemists. They provide us with chronometers with which to constmct the sequence of events that led to the solar system we live in, and they provide us with probes of stellar nucleosynthesis and the environment in which our solar system formed. These topics appear throughout this book and will be discussed in detail in Chapters 8, 9, and 14. 

Since its original description at the semiempirical level, COSMO has also been generalized to the ab initio and density functional levels of theory as well (Klamt et al. 1998). In addition, conductor-like modifications of the PCM formalism have also been described, and to distinguish between the conductor-like version and the original (dielectric) version, the acronyms C-PCM and D-PCM have been adopted for the two, respectively (Barone and Cossi 1998). 

This chapter was originally planned as a review of the state of modem cosmology however, on reflection, I decided that a more creative use of the opportunity to contribute to this volume would be to lay before the reader certain well-founded observational results that, at the very least, indicate that our cosmos is not quite as well understood as we are commonly inclined to believe. 

Fig. 8.1. Original diagrams of the first COSMO-RS phase-diagram calculations by Iven Clausen [96] for four alcohol-water mixtures (methanol at 60 C, ethanol at 55 °C, 1-propanol at 60 °C and 1-butanol...

As a final attempt to understand the origin of the unexpectedly low slope, we split AG into four different parts, i.e., the quantum chemical gas-phase dissociation, the COSMO-interaction energies of the neutral and the ionic species and the chemical potential difference from COSMO-RS. On the basis of these reasonably independent descriptors, we performed a multilinear regression of pKa yielding an almost identical regression coefficient and rms error as before with slopes ranging from 0.55 to 0.62 for the four contributions. Thus all contributions—although very different in nature—show the same unphysical slope with respect to the pKa. 

Fig. 11.11. Evaluation of COSMO/rag performance for logAow on a large data set. The original method yielded 0.39 log-units MAE, while COSMO/rag gives 0.57. When corrected for the systematic shift, the MAE of COSMO/rag reduces to 0.42.

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