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I.A.2.

Using the CCCBDB

The CCCBDB is set up to allow you to get experimental data, calculated data and comparisons between experimental and calculated data. The general design is to allow you to specify what you want in the following order:
1) choose a property (such as calculated vibrational frequencies)
2) choose a molecule (or molecules)
3) choose a calculational method and a basis set (such as B3LYP/6-31G*).

Choosing a property

The index in the left frame lists several broad categories, which are subdivided into properties. For example the calculated data (section III) has subsections:
  1. geometry
  2. Vibrations
  3. Entropies
  4. Energetics
  5. Electrostatics
  6. Information about calculations
  7. Compare calculations
Each of these is further divided into specific properties, such as rotational constants (under geometries) or Mulliken charges (under electrostatics). Some of the properties may be found under several categories.

Specifying a molecule

When asked for a formula the CCCBDB can recognize entries such as CH3OH or (CH2)3O. The formula parser does not distinguish between different arrangements of the atoms: CH3COCH3 and C3H6O will both bring up a list of the five isomers of C3H6O present in the CCCBDB. The formula parser will also accept wild cards: a question mark (?) indicates one or more of the preceding atom, and an asterisk (*) indicates zero or more of the preceding atom. For example the formula C3H*Cl? returns the following five species from the CCCBDB:
CH2ClCH2CH3Propane, 1-chloro-
CH3CHClCH3Propane, 2-chloro-
CH2ClCHClCH3Propane, 1,2-dichloro-
CH3CCl2CH3Propane, 2,2-dichloro-
C3H5Cl3Propane, 1,2,3-trichloro-
A comma delimited list of molecules can also entered: CH4,C2H6,C3H8,C4H10
The formula parser can also handle Chemical Abstract Service (CAS) numbers and a few common names. Thus CH4, H2CH2, methane, and 74828 are all equivalent.
As well as using wild cards to specify a group of molecules there is a page for choosing molecules by atom types, bond types, and chemical groups. This page is accessed by clicking on the "choose chemical groups" link instead of entering a formula.