Non-electronic computers

The definition en by Coulson for this second branch of quantum chemistry has not been a well selected choice. Coulson spoke of "non-electronic computers", when the use of computers to examine "chemical concepts" and to elaborate new interpretation tools was already initiated. Within few years from the Coulson analysis the computer become the main instrument for interpretation (or description). 

The Supplement B (reference) contains a description of the process to render an automatic construction of mathematical models with the application of electronic computer. The research work of the Institute of the applied mathematics of The Academy of Sciences ( Ukraine) was assumed as a basis for the Supplement. The prepared mathematical model provides the possibility to spare strength and to save money, usually spent for the development of the mathematical models of each separate enterprise. The model provides the possibility to execute the works standard forms and records for the non-destructive inspection in complete correspondence with the requirements of the Standard. 

The definitions given by Coulson to quantum ehemists belonging to this group (electronic computers, or ab initio-ists) is surely outdated. Every quantum chemists is now an "electronic computer" and the differenee between ab-initioists and non ab-initioists is rather... 

Since 1967, CA abstracts have been numbered sequentially in each (semiannual) volume of Chemical Abstracts-, the abstract number includes a computer-generated check letter. Before the introduction of computer-assisted production in 1967, abstracts were located in CA indexes by the sequentially numbered columns on each page in each issue. The letters a to i were also assigned to every column to assist in the location of the abstract. Before 1947, a superscript number was used instead of a letter. These older methods did not give each abstract a unique identifier. In SciFinder, all pre-1967 abstracts have been assigned a unique abstract number. These new CA abstract numbers cannot be used to find abstracts in printed (non-electronic) pre-1967 Chemical Abstracts, and are a potential source of confusion if this distinction between the procedures for locating pre- and post-1967 abstracts is not appreciated. 

As to the all-electrons non-empirical computations, they are based on the Roothaan LCAO SCF-method 8>, most of the applications in biochemistry using atomic basis sets of Gaussian functions 9>. 

It is thus seen that for the first property which we have considered, the dipole moment, quantitative predictions could be made with reasonable accuracy, even in the -electrons era, with sufficient care and some training. The more elaborate computations have essentially brought confirmation of the main trends. For ionization potentials, the precision gained is more considerable, especially as concerns the relative locations of the ir and lone-pair ionizations. (The separation of the highest ir orbital and highest o orbitals being over 1.5 eV in non-empirical computations, it is probable that correlation effects would not modify the relative ordering of the ir and o ionization potentials)... 

The first pharmacy disease-management examinations were offered in 1998 as pencil-and-paper tests in the states of Arkansas, North Dakota, and Mississippi. Certification was offered in four disease states asthma, dyslipidemia, diabetes, and anticoagulation therapy. Since that time, the examinations have been adapted for computer administration at multiple test sites any time of the year. However, non-electronic testing is offered annually at the APhA national meeting. Due to the specialized funds of knowledge required for successful certification, pharmacists are strongly encouraged to have at least 2... 

Vibrational spectroscopy represents two physically different, yet complementary spectroscopic techniques IR and Raman spectroscopy. Although both methods have been utilised for many years, recent advances in electronics, computer technologies and sampling made Fourier transform infrared (FTIR) and Raman (FT-Raman) one of the most powerful and versatile analytical tools. Enhanced sensitivity and surface selectivity allows non-invasive, no-vacuum molecular level analysis of surface and interfaces. Emphasis is placed on recent advances in attenuated total reflectance (ATR), step-scan photoacoustic (SS-PA), Fourier transform infrared (FTIR) and FT-Raman microscopies, as utilised to the analysis of polymeric surfaces and interfaces. A combination of these probes allows detection of molecular level changes responsible for macroscopic changes in three dimensions from various depths. 7 refs. 

Chemistry is an experimental subject whose results can be built into a pattern around quite elementary concepts. The role of quantum chemistry is to understand these concepts and to show what are the essential features of chemical behaviour. To say that the electronic computer shows that D(H-F) >> D(F-F) is not an explanation at all, but merely a confirmation of experiment. Any acceptable explanation must be in terms of repulsions between non-bonding electrons, dispersion forces between atomic cores and the like. 

The enormous progress of electronic computers has allowed physico-chemical systems to be accurately described (by means of new theoretical disciplines like computational physics and theoretical chemistry) via numerical solution of the basic equations. This hard modelling of physico-chemical systems is characterized by extended numerical computations ab initio methods accurate description of the system specificity but non extensibility of the results from one system to another. 

Progress on the theoretical description at the properties of moderately dense and dense fluids systems has traditionally been limited by the lack of an equation of state for dense fluid phases. The past decade has seen rapid progress on this problem using electronic computers to obtain ensemble average properties for fluid systems modelled with simple particles. The equilibrium and non-equilibrium statistical mechanical and kinetic theory relationships admit the direct calculation of the fluid properties without identifying the mathematical form of the equation of state. This application of computers has revolutionized the fluid properties studies in ways as profound as their application to process design problems. 

In the work of Thonhauser and coworkers [57], the derivative of the functional with respect to the electron density was derived, thus allowing self-consistent vdW-DFl computation. Self-consistent calculations require more computational time ( X 2 compared to the corresponding DFT GGA procedure), but allow the computation of accurate Hellmann-Feynman forces. Usually, the results of SC- and non-SC computations have negligible differences. However, self-consistency and corresponding self-consistent densities are important when monomers are pushed together or the systems undergo significant density redistributions upon the formation of the van der Waals bond. If near-equilibrium structures are considered, density redistribution may take place upon formation of the van der Waals bond. In fact, it is rather small electrons/A ) and is... 

The chromatogram can finally be used as the series of bands or zones of components or the components can be eluted successively and then detected by various means (e.g. thermal conductivity, flame ionization, electron capture detectors, or the bands can be examined chemically). If the detection is non-destructive, preparative scale chromatography can separate measurable and useful quantities of components. The final detection stage can be coupled to a mass spectrometer (GCMS) and to a computer for final identification. 

---