Extracting Thermochemical Information from ab Initio Data Part 2

Presented at NATO ASI on "Energetics of Stable Molecules and Reactive Intermediates,", Castelo Branco, Portugal, July 1998

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Table of Contents

Extracting Thermochemical Information from ab Initio Data Part 2

Unique considerations for ab initio thermochemistry

Absolute energies

Reaction scheme is important

Most heats of formation are not really “ab initio”

Total molecular energy?

Total atomization energy?

Isogyric reactions

Isogyric reaction #1

Isogyric reaction #2

Be a chemist!

Isodesmic reactions

Isodesmic reaction #1

A test for correlation balance

Isodesmic reaction #2

Isodesmic reaction #3

Homodesmic reaction

How reliable are the results?

Wavefunction diagnostics are needed

Future precision bottlenecks

Future scope

Summary (when reading critically or doing)

Author: Karl Irikura
            Computational Chemistry Group
              Physical and Chemical Properties Division
              National Institute of Standards and Technology
              Gaithersburg, MD 20899-8380 

Email: karl.irikura@nist.gov