comparison of compound methods
Geometrical parametres formamidilnogo radical HNC (O) H (Tables 4.3, 4.4) are received with use [226]. It has been above shown, that in calculations for the same basis, but with various methods, the equilibrium structure formamidilnogo rayodikala can differ considerably, up to transferring to other point group simyometrii.
So table 4.3 contains the parametres which are falling into to nonplanar structure HNCOH, and Table 4.4 - to flat. Thus, equilibrium geometry in calculation «meyotod_1/bazis_1 », can not coincide essentially with that for"metod_2/bazis_2"if«метод_1»falls into to Table 4.3, and«метод_2»it is taken from Table 4.4. I.e. the condition blizoyosti geometry is not observed. Moreover, the analysis shows, that the geometry forms - dilnogo a radical from Table 4.4 is a transient state (TS) between two nonplanar conformstions (optical isomerides) found by means of methods of Table 4.3. ^edovatelno, Etotaιформамидильного a radical, defined by means of« metod_2/bazis_2//metod_1/bazis_1 », in any combination« metod_2/.//metod_1/. », if methods undertake from different tables, corresponds not to an equilibrium state, and TS. Cushche - stvujut and other connections (for example, CH3NO2 [303]) for which equilibrium geometyorija in"metod_1/bazis_1"that is not in"metod_2/bazis_2".
Tables 4.3 and 4.4 contain all steps by definition Etotaιиз G-w, CBS-w. If to analyse all sequence of procedures of any of specified difficult soyostavnyh methods [281, 299] it will appear, that the equilibrium geometry formamidilnogo a radical is in G-wi CbS-ws the help "metoda_1/bazisa_1" from Table 4.3, and Etota ι (and Htota ι) - "metodom_2/bazisom_2" from Table 4.4. ^edovatelno, difficult compound meyotody yield Etotaιи Htotalформамидильного a radical for essentially nonequilibrium geoyometrii (close to TS) and cannot be used at definition of standard enthalpy of formation HNC (O) H. At the same time, it is necessary to notice, that compound methods (as spoyosob definitions Etota ι) are applicable in all cases, but EtotaI, probably, will concern not a minimum on Ш1Э, and to any other point.
Use as simple («metod_2/bazis_2//metod_1/bazis_1»), and difficult (G-w, CBS-w, W-w) compound methods bears in itself a certain share of luck. If geoyometrija, optimised at the first stage, remains equilibrium for the subsequent etayopov use of these methods is justified. If the yielded condition is not carried out, application of compound methods for definition of thermodynamic properties in dalnejyoshem will inevitably lead to incorrect result. 1ри it, the total error ∆y H0будет, first of all, to be defined by a deviation of geometry from equilibrium on each of steps. For example, application of difficult compound methods or a certain configuration simple («метод_1» from Table 4.3, «метод_2» from Table 4.4 and, naoboyorot) for formamidilnogo a radical is incorrect.
Probably with it, in opredeyolennoj to a measure, known difficulties of difficult compound methods, partially reyoshaemye by introduction «vysokourovnevyh empirical corrections» [300-302] are connected.Thermodynamic and thermochemical properties of molecules and radicals in sootvetyostvujushchih databases are classified as: "recommended" ("tabulated"), "pre-award", "doubtful" and "unacceptable" (see, for example, [127]). C this
The points of view ΔfH0и other properties HNC (O) H, found by means of G-n, CBS-n, W - n, fall into "unacceptable", and the properties of other substances found without any comparisons, it is necessary to classify as "doubtful" or, at the best, "pre-award". The considered example shows, that use of compound methods demands special attention when on each step of calculation, and not just at a stage of optimisation of geometry, convergence conditions should be resulted. Those are differences energy and standard deviations of factors of a matrix of density in last cycle of iterative procedure. Besides it is necessary to result and proveyorjat values of forces (gradients), and, on-possibility, vibration frequencies. Discrepancy of the specified sizes (the big gradients, imaginary frequencies) is powerful argument for refusal of corresponding value of energy. Modern computer programyomy give out the specified sizes on each step (except for a spectrum), and prevysheyonie certain borders will speak about inapplicability of compound methods in rasyosmatrivaemom a case. Full of energy of reference-point substances are shown in Tables 4.5 - 4.9.
Table 4.6. Full energy-Etota ι//-alkanes and/-alkilnyh the radicals, calculated metoyodom B3LYP/6-311 ++ G (3df, 3pd) in program GAUSSIAN, in a.e.
Molecule | AND, G | AND, IN | Δ, a kdzh/MOLE | Radical | AND, G | AND, IN | Δ, a kdzh/MOLE |
С2Н6 | 79,862776 | 79,864128 | -3,5 | CH3CH∙2 | 79,191139 | 79,192494 | -3,6 |
C3H8 | 119,190195 | 119,192292 | -5,5 | CILCH-CIU | 118,518302 | 118,520397 | -5,5 |
С4Н10 | 158,517448 | 158,520277 | -7,4 | CH3 (CH2) 2CH∙2 | 157,845598 | 157,848423 | -7,4 |
С5Н12 | 197,844621 | 197,848177 | -9,3 | CH3 (CH2) 3CH∙2 | 197,172781 | 197,176333 | -9,3 |
C6 ‰ | 237,171797 | 237,176088 | -11,3 | CH3 (CH2) 4CH∙2 | 236,499962 | 236,504242 | -11,2 |
С7Н16 | 276,498972 | 276,503992 | -13,2 | CH3 (CH2) 5CH∙2 | 275,827138 | 275,832152 | -13,2 |
С8Н18 | 315,826125 | 315,831871 | -15,1 | CH3 (CH2) 6CH∙2 | 315.154269 | 315,160012 | -15,1 |
С9Н20 | 355.153248 | 355.159798 | -17,2 | CH3 (CH2) 7CH∙2 | 354.487919 | - | |
С10Н22 | 394.480412 | 394.487700 | -19,1 | CH3 (CH2) 8CH∙2 | 393.808590 | 393,815863 | -19,1 |
In - the Cartesian functions (6d 10f), G - spherical harmonics (5d 7f)
Δ - a difference full energy, found by means of B3LYP/6-311 ++ G (3df, 3pd) 6d
10f and B3LYP/6-311 ++ G (3df, 3pd) 5d 7f
Table 4.7. Full energy Etota ι///-nitroalkanes and/-nitroalkilnyh radicals, rasschi -
tannaja a method. | 33LYP/6-311 ++ G (3df, 3pd) in various bases, in a.e. | |||
Molecule | AND, G GAUSSIAN | A IN GAUSSIAN | Radical | G GAUSSIAN |
CH3NO2 | -245.109670 | -245.115019 | CH7NO7 | -244.462639987 |
C2H5NO2 | -284.440728 | -284.446685 | C2H4NO2 | -283.794201717 |
C3H7NO2 | -323.768111 | -323.774912 | C3⅛NO2 | -323.126162972 |
C4H9NO2 | -363.095468 | -363.103007 | C4H8NO2 | -362.457330055 |
C5H11NO2 | -402.422747 | -402.431006 | C5H10NO2 | -401.788722687 |
(HNLL | -441.749994 | -441.758987 | C6H12NO2 | -441.119782583 |
C7Hl5NO2 | -481.077194 | -481.086922 | C7H14NO2 | -480.450804709 |
C8H17NO2 | -520.404387 | -520.414785 | C8H16NO2 | - |
C9H19NO2 | -559.731572 | -559.742689 | C9H18NO2 | - |
C10H21NO2 | -599.058752 | -599.070669 | - | - |
And - basis 6-311 ++ G (3df, 3pd), - basis aug-cc-pVQZ
In - the Cartesian functions (6d 10f), G - spherical harmonics (5d 7f) * 5d 7f
** GAUSSIAN b3lyp∕aug-cc-pv5z 5d 7f
сGAUSSIAN b3lyp∕cc-pvQZ 6d 10f
Table 4.8. Full energy of formamide-Etota ι, in a.e. (1 a.e. = 2625,4997 kdzh/MOLE). For compound methods the empirical correction »HLC (⅞⅛ piric) ∙ is specified« vysokourovnevaja
Method | Etotal | EEmpiric | EEmpiric * | Method | Etotal | EEmpiric | EEmpiric * | Method | Etotal |
G1 | 169,686273 | 0,055260 | 145,09 | CBS - 4M | 169,722779 | 0,116078 | 304,76 | B3LYP∕6 - 311 ++ G (3df, 3pd) 5d 7f | 169,967074 |
G2 | 169,686273 | 0,055260 | 145,09 | CBS - 4O | 169,720680 | 0,113450 | 297,86 | B3LYP∕6 - 311 ++ G (3df, 3pd) 6d 10f | 169.970400 |
G2 MP2 | 169,684916 | 0,045000 | 118,15 | CBS - Lq | 169,745365 | 0,106490 | 279,59 | B3LYPAUG-CC - pV5Z 5d 7f | 169,986327 |
G3 | 169,828853 | 0,057474 | 150,90 | CBS-Q | 169,697047 | 0,026694 | 70,09 | MP2 (full) ∕6 - 311 ++ G (3df, 3pd) | 169,679715 |
G3B3 | 169,832326 | 0,060840 | 159,74 | CBS - QB3 | 169,698421 | 0,029031 | 76,22 | MP2∕aug-cc-pV 5Z | 169,686688 |
G3 MP2 | 169,711304 | 0,083511 | 219,26 | CBS - APNO | 169,893440 | 0,008187 | 21,49 | MP4SDTQ∕6 - 311 ++ G (3df, 3pd) | 169,652496 |
G3 MP2B3 | 169,718248 | 0,090369 | 237,26 | W1 | 170,025359 | 0,00 | 0,00 | - | - |
*в a kdzh/MOLE
Table 4.9. Full energy formamidilnogo a radical-Etota ι, in a.e.
HFAUG-CC - pV5Z | MP2AUG - cc-pVQZ | MP4SDTQ ∕ 6-311G (d, p) | B3LYP ∕ AUG-CC - pV5Z | CCSD (T) 6-311 ++ G (3df, 3p d) | QCISD∕6 - 311 ++ G (3df, 3pd) | CISD∕6 - 311 ++ G (3df , 3pd) | CID∕6 - 311 ++ G (3d f, 3pd) |
168.372422 | 168,968402 | 168,844355 | 169.294053 | 168.956125 | 168.934057 | 168.867788 | 168.864761 |
4.3.
More on topic comparison of compound methods:
- a simple compound method. The basic lacks of simple compound methods.
- difficult compound methods: families GAUSSIAN-n, CBS-n, W-n.
- Methods differ on comparison term.
- 1.1. Methods of revealing and comparison of national specificity of semantics of a word. A technique kontrastivnogo descriptions
- comparison ROUND PZH and neoadjuvantnoj GT as preventive maintenance methods infravezikalnoj obstructions after brahiterapii
- comparison of methods DFT and MP2, the theorem account viriala, an estimation of an error of incompleteness of basis.
- definition of methodological principles of knowledge of the right: taking into account comparison of is natural-scientific methodology and jurisprudence methods
- Bezekvivalentnye compound terms and their transfer
- 2.2.2. Types compound epitetnyh complexes
- 3.2.1 Influence of concentration of peroxide compound of hydrogen and rn for speed of dissolution
- 2.2.1. The Is formal-semantic characteristic of compound terms IJA
- the Mechanism of dissolution of nickelous sulphide in hydrogen peroxide compound
- 3.2 Kinetic laws of dissolution of nickelous sulphide (II) in solutions of peroxide compound of hydrogen
- Construction of mathematical models of processes of dissolution of nickelous sulphide in solutions of peroxide compound of hydrogen
- 3.3.2.2. ekstsrsrnaja the characteristic of a body of fishes and a chemical compound.
- 2.3.1. Divergences in morfo-syntactic structure of English compound terms and their Russian equivalents
- CHAPTER 4. TEMPERATURE AND FIELD TRANSFORMATION OF DOMAIN STRUCTURE OF INTERMETALLIC COMPOUND Ho2Fei7HA OF THE SURFACE (120)