Determination of Molecular Properties

A. Hinchliff, Ah Initio Determination of Molecular Properties Adam Hilger, Bristol (1987). 

Tab. 13.1 Maximum and average errors (relative to experiment) for CCSD(T) using an spdjg-type basis set in the determination of molecular properties for a number of small molecules containing first-row atoms and hydrogen. Data taken from Ref. [12].

It has been said of semiempirical methods They will never outlive their usefulness for correlating properties across a series of molecules... I really doubt their predictive value for a one-off calculation on a small molecule on the grounds that whatever one is seeking to predict has probably already been included in with the parameters. (A. Hinchliffe, Ab Initio Determination of Molecular Properties , Adam Hilger, Bristol, 1987, p. x). Do you agree with this Why or why not Compare the above quotation with ref. [24], pp. 133-136. 

Coriani. S. Ab initio determination of molecular properties. Ph.D. Thesis, U niversity of Aarhus (2000)... 

The RECP approach delivers a balanced treatment of relativity and electron correlation for transactinide compoimds at relatively low cost. Spin-orbit effects are usually small, however, the inclusion of electron correlation is necessary for any accurate determination of molecular properties. It appears that coupled-cluster calculations using scalar relativistic ECP, i.e. AREP, will be reasonably accurate for most groimd state properties of the d-block transactinide compounds, provided that spin-orbit corrections are included somehow in the final estimate of energy differences. 

While methods for studying these and other types of changes in the sample have become widely used, the most widely used methods are thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). As a group, thermal methods of analysis now constitute the most widely used experimental techniques in the chemical industry. A major reason for this widespread use is that determination of bulk properties, thermal stabdity, and characterization of materials are as important in industrial appHcations as are the determination of molecular properties. 

Quantum chemistry applies quantum mechanics to problems in chemistry. The influence of quantum chemistry is evident in all branches of chemistry. Physical chemists use quantum mechanics to calculate (with the aid of statistical mechanics) thermodynamic properties (for example, entropy, heat capacity) of gases to interpret molecular spectra, thereby allowing experimental determination of molecular properties (for example, bond lengths and bond angles, dipole moments, barriers to internal rotation, energy differences between conformational isomers) to calculate molecular properties theoretically to calculate properties of transition states in chemical reactions, thereby allowing estimation of rate constants to understand intermolecular forces and to deal with bonding in solids. 

DETERMINATION OF MOLECULAR PROPERTIES FROM THE FINE STRUCTURE OF X-RAY ABSORPTION BANDS... 

Hinchliffe A. 1987. Ab Initio Determination of Molecular Properties. Adam Hilger Bristol. Hoffmann M. R. and Dyall K. G. (eds.) 2002. Low-Lying Potential Energy Surfaces (ACS Symposium Series 828). American Chemical Society Washington, DC. 

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