MM2 and Minimizing

[204416834]

Hi, for the chart on page 4 when we are trying to find the bond lengths for benzene and ketone and ether CO bonds, how many times should we minimize the energy? Some people were saying to do it until the optimal and ideal bond lengths on the chart on the left have the same numbers.

[Chem_Mod]

After you draw the molecule, minimize the energy. If you minimized it correctly and place your cursor over the bond, it will give you the length.

[204416834]

But if you minimize it twice, the answer is different from when you minimize it once..how do you know how many times you have to minimize it before you get the right bond length?

[Chem_Mod]

Build the molecule, minimize it once, and then pull up the calculated values. The algorithms used by ChemDraw are extremely sensitive and you might not get the same value as another person but they should be VERY close. To be consistent, we've been telling people to minimize exactly once after building.