EREDs

MAXIMUM LIKELIHOOD ESTIMATION OF OAnAMETEPS FoOM VLE DCONTROL PARAMETERS K ERE SET AS FOLLOWS -... 

ERE error flag. Integer variable normally zero ERE =... 

VAPOR COMPOSITIONS Z. ENTH RETURNS ERE=0 UNLESS BINARY DATA ARE... 

Very finely divided minerals may be difficult to purify by flotation since the particles may a ere to larger, undesired minerals—or vice versa, the fines may be an impurity to be removed. The latter is the case with Ii02 (anatase) impurity in kaolin clay [87]. In carrier flotation, a coarser, separable mineral is added that will selectively pick up the fines [88,89]. The added mineral may be in the form of a floe (ferric hydroxide), and the process is called adsorbing colloid flotation [90]. The fines may be aggregated to reduce their loss, as in the addition of oil to agglomerate coal fines [91]. 

Til ere are three types of calcii lation s in HyperCh ein sin file point, geoin etry optimi/atioii or m iniin i/ation, an d in oleciilar tlyn am ics. 

To fin d a first order saddle poiri t (i.e., a trail sition structure), a m ax-imiim must be found in on e (and on/y on e) direction and minima in all other directions, with the Hessian (the matrix of second energy derivatives with respect to the geometrical parameters) bein g varied. So, a tran sition structu re is ch aracterized by th e poin t wh ere all th e first derivatives of en ergy with respect to variation of geometrical parameters are zero (as for geometry optimization) and the second derivative matrix, the Hessian, has one and only one negative eigenvalue. 

HypcrCb cm in tegrates cq tiation s 26 an d 27 to describe tb c mot ion s of atom s. In the absence of temperature regulation, tli ere are no external sources or depositories of energy, fhat is. no other energy terms exist in the Hamiltonian, and the total energy of the system is con slant. 

You can use multiple basis sets in a single inoleeular system. I ti e Apply Basis E3et m HyperChem applies the currently selected basis set to the selected atom s or to all the atom s in IlypcrChem if th ere is no current selection. For example, some heavy atoms might have a b-1 IG basis set (s and p only) while other heavy atoms m igh t use a 6-151 CE basis set (with d-orbitals). Th is is an iiii usual but flexible option for ah miiro calculalioiis. 

You can usually use the default values. If the calculation exceeds the iteration limit before it reaches the convergcriec limit, llieti th ere is m osl I ikely con vergeri ce failti re. Sim ply in creasin g tli e limits is un likely to help, I ll e nils COM vergeii ce accelerator, (see SCF Convergence on page 47), wli ich is available for all the SCF... 

I,argc am plitudc (floppy) vibi aLion al tit odes ofLeti exli ihit sign ifi-can t an h arm on ieity that tn ay increase errors in com pti ted freqticn -cies. In addition to an h armon icily, usually Lh ere is coiiplin g between vibrational modes. 

Note Do not use CNDO on any problem wh ere electron-spin is critically irn p or tan t. Its com pi etc neglect of atom ie ex eh au ge in te-grals makes it incapable of dealing with these problems. 

AtomTypeMass is set to the nam e of th e file that lists the atom types associated with the force field and their masses (masses are associated with a type h ere not an atomic n umber). Th e file can have any name hut by convention isnamed, for example, as amheiTyp.txtfdbn. 

I h e n otation h ere rn ean s th at electron 1 occupies a spatial orbital tpi with spin up (no bar on top ] electron 2 occupies spatial orbital tPi with spin down (a baron top), and so on. An RIIF description of the doublet S=l/2 slate obiamed by adding an electron to would be... 

HyperChcin s ah mitio calculations solve the Roothaan equations (.h9 i on page 225 without any further approximation apart from th e 11 se of a specific fin iie basis set. Th ere fore, ah initio calcii lation s are generally more accurate than semi-enipirical calculations. They certainly involve a more fundamental approach to solving the Sch riidiiiger ec nation than do semi-cmpineal methods. 

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