ALPHA START VALUE

[Luca Saraconi]

Hi all,

I am a rookie in using Calpuff and I am still looking for the parameters needed for the model.

One of them is really tricky for me, "ALPHA START" that should be the aqueous dissociation constant of a substance. I have several question about it:

1) What is it really? I can't recognize any value already reported in the software. It does not correspond with the definition I gave (and I read) earlier.

2) Is there some value to state in the software that a substance does not give any kind of dissociation in aqueous phase? For example, a value of "1" could be read from the software as a substance which does not give any dissociation. 

3) Do you know how it is estimated or some sources where I can find this value for several substances?

Thank you very much to anyone who can help me!