Table translator

To meet these conditions a special chemical programming language CHMTRN (Chemical Translator) was developed. By use of a special assembler - TBLTRN (Table Translator, written by Dr. Donald E. Barth), it was possible to convert the CHMTRN tables into specially encoded FORTRAN BLOCK DATA statements which could be loaded with LHASA or read in at run time. 

The basic approach of CHMTRN is that there are keywords (currently several hundred) that have 

If this name conflicts or duplicates that of some other chemical program, I apologize. The duplication is unintentional. 

ACS Symposium Series American Chemical Society Washington, DC, 1977. 

LHASA contains an interpreter called EVLTRN (Evaluate Transform) which decodes the bit patterns and performs the requested queries about the current structure or performs a specified operation. As an example, consider a line from the tables which says 

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From the information on the right side of the C3v eharaeter table, translations of all four atoms in the z, x and y direetions transform as Ai(z) and E(x,y), respeetively, whereas rotations about the z(Rz), x(Rx), and y(Ry) axes transform as A2 and E. Henee, of the twelve motions, three translations have A and E symmetry and three rotations have A2 and E symmetry. This leaves six vibrations, of whieh two have A symmetry, none have A2 symmetry, and two (pairs) have E symmetry. We eould obtain symmetry-adapted vibrational and rotational bases by allowing symmetry projeetion operators of the irredueible representation symmetries to operate on various elementary eartesian (x,y,z) atomie displaeement veetors. Both Cotton and Wilson, Deeius and Cross show in detail how this is aeeomplished. 

Levi, Primo.The periodic table translated by Raymond Rosenthal. Translated by Raymond Rosenthal. New York Schocken, 1984. 

Memorize the table Translating Words to Mathematical Operations on page 241. 

Levi, Primo. The Periodic Table. Translated by Raymond Rosenthal. Schocken Books, New York. 1984. 

Fig. 4.5 Ribbons of helical data as acquired from helical CT. (a) When the pitch is less than 1, such as in a four-channel system, and the table translation equals three channels, the ribbon acquired from the first channel of the second rotation will overlap the ribbon of the fourth channel of the first rotation, (b) When the pitch is greater than 1, more longitudinal area can be covered however, the helical data ribbons do not overlap, so each ribbon must receive a sufficiently high X-ray dose to obtain a diagnostic image and the advantages of overlapping data cannot be used...

Primo Levi, Il sistema periodica (Torino Einaudi 1975) The Periodic Table, translated from the Italian by Raymond Rosenthal (London Campbell, 1995). 

Table 1 Experimental results obtained for D=(350 2) mm y Act=(5° 2 ). x is the axial translation and Xe is the experimental value obtained from Eq. (1).

The last two colimms of the character table give the transfonnation properties of translations along the v, y. 

These include rotation axes of orders two, tliree, four and six and mirror planes. They also include screM/ axes, in which a rotation operation is combined witii a translation parallel to the rotation axis in such a way that repeated application becomes a translation of the lattice, and glide planes, where a mirror reflection is combined with a translation parallel to the plane of half of a lattice translation. Each space group has a general position in which the tln-ee position coordinates, x, y and z, are independent, and most also have special positions, in which one or more coordinates are either fixed or constrained to be linear fimctions of other coordinates. The properties of the space groups are tabulated in the International Tables for Crystallography vol A [21]. 

The apparatus consists of a tip-position controller, an electrochemical cell with tip, substrate, counter and reference electrodes, a bipotentiostat and a data-acquisition system. The microelectrode tip is held on a piezoelectric pusher, which is mounted on an inchwomi-translator-driven x-y-z tliree-axis stage. This assembly enables the positioning of the tip electrode above the substrate by movement of the inchwomi translator or by application of a high voltage to the pusher via an amplifier. The substrate is attached to the bottom of the electrochemical cell, which is mounted on a vibration-free table [, and ]. A number... 

Table B2.5.3. Product energy distribution for some IR laser chemical reactions. (E ) is the average relative translational energy of fragments, is the average vibrational and rotational energy of polyatomic fragments, and/ is the fraction of the total product energy appearing as translational energy [109],...

In the sixth column of the main body of the character table is indicated the symmetry species of translations (7) of the molecule along and rotations (R) about the cartesian axes. In Figure 4.14 vectors attached to the nuclei of H2O represent these motions which are assigned to symmetry species by their behaviour under the operations C2 and n (xz). Figure 4.14(a) shows that... 

Then, if we look through all the point group character tables in Appendix A to see if any of the translational symmetry species is totally symmetric, it is apparent that molecules belonging to only the following point groups have a permanent dipole moment ... 

A molecule has a permanent dipole moment if any of the symmetry species of the translations and/or T( and/or 1/ is totally symmetric. Using the appropriate character table apply this principle to each of these molecules and indicate the direction of any non-zero dipole moment. 

However, we know that a non-linear moleeule has three rotational and three translational degrees of freedom, all of whieh ean be assigned to symmetry speeies (Seetion 4.3.1). These are indieated in Table 6.5 and subtraeted from the total number of degrees of freedom to give the total number of vibrational degrees of freedom. 

In Table 6.6 the results for the point group are summarized and the translational and rotational degrees of freedom are subtracted to give, in the final column, the number of vibrations of each symmetry species. 

Look up the translational symmetric species in the relevant character table. 

The vibrations of acetylene provide an example of the so-called mutual exclusion mle. The mle states that, for a molecule with a centre of inversion, the fundamentals which are active in the Raman spectmm (g vibrations) are inactive in the infrared spectmm whereas those active in the infrared spectmm u vibrations) are inactive in the Raman spectmm that is, the two spectra are mutually exclusive. Flowever, there are some vibrations which are forbidden in both spectra, such as the torsional vibration of ethylene shown in Figure 6.23 in the >2 point group (Table A.32 in Appendix A) is the species of neither a translation nor a component of the polarizability. 

The A B2u — X Aig system of benzene (see Section 7.3.1.3), shown in Figure 7.42, is a particularly interesting one. It is electronically forbidden, since 52 is not the symmetry species of a translation (see Table A.36 in Appendix A) therefore (/ g)eq is zero and the Oq band is not observed. All the intensity derives from the second term on the right-hand side of Equation (7.131) and most of it through the U2g vibration Vg. Since... 

The A A2 X Ai, n -n system of formaldehyde (see Section 7.3.1.2) is also electronically forbidden since A2 is not a symmetry species of a translation (see Table A.l 1 in Appendix A). The main non-totally symmetric vibration which is active is Vq, the hj out-of-plane bending vibration (see Worked example 4.1, page 90) in 4q and d transitions. 

For example, a polypeptide is synthesized as a linear polymer derived from the 20 natural amino acids by translation of a nucleotide sequence present in a messenger RNA (mRNA). The mature protein exists as a weU-defined three-dimensional stmcture. The information necessary to specify the final (tertiary) stmcture of the protein is present in the molecule itself, in the form of the specific sequence of amino acids that form the protein (57). This information is used in the form of myriad noncovalent interactions (such as those in Table 1) that first form relatively simple local stmctural motifs (helix... 

Typical speciftcations of technical-grade phosphonic acid are given in Table 12. Because disposal of the by-product hydrochloric acid poses problems, several attempts have been made to produce phosphonic acid by a nonhalide route however, so far none of these efforts have been translated into an industrial process. 

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