Faced with this screen you can go through the properties and pick a Calculation Method for each property you want. The calculation method can be; retrieval from the database (either the System, User or a previously calculated value), entry by the user or one of the many relationships included in the system.

Some of the relationships are corresponding states (properties related to critical point properties) methods which require other properties, or group contribution methods, requiring entry of the groups in the molecule.

When other properties are required for the calculation of the property of interest the user will be alerted by a series of colored lights as to other methods that must be selected. Not attempt will be made to calculate a property if a method has not been selected for all supporting properties (those used in the calculation).

In the example below the Lydersen method was selected for the cacluation of Tc. Normal boiling point is required in this calculation. A round YELLO light next to Tc indicates that a method has been select, but not calculated yet. It cannot be calculated because no method has yet been selected for Tb, indicated by the RED square box.

Now select the Calculate Button from the Windows Menu.

The system will calculate properties in the order they are needed, those from the DB first, then those with no dependents, then those with dependents. Here the user will be prompted for Tb first.

Next, because the Lydersen Method Requires Group Contributions, you are prompted for those at this time. This information will be saved in the database and anytime in the future that you calculate any property by Lydersen's Methods, this screen will appear populated as you see it above, you will not have to reenter the groups, unless you want to.

Finally, all properties are available.

Note that you can change the units to whatever you would like. Also the buttons on the far right jump you directly to help on the specific method.