CCL:G: SN1 reaction

 Sent to CCL by: "Nguyen Minh Ly" [nguyenminhly2209,yahoo.com]
 I have a problem to discuss. I survey the SN1 reaction of tert-butyl chloride
 and OH- by:
 1 / Optimization of structures with Gaussian
 2 / Optimize to find the transition state in the first stage of the SN1
 reaction (using QST2 keyword)
 As we all know, this reaction depends on the concentration of OH-. If
 concentration of OH- is low (dilute solution), the reaction will occur SN1. If
 concentration of OH- is high (special solution), the reaction will occur E1.
 But in GaussView, when I optimized to find the transition state in the first
 stage of the SN1 reaction, I can only draw a molecule C4H9Cl and a OH- in
 Reactants window, a molecule C4H9OH and a Cl- in products window. This means
 that the rate of C4H9Cl and OH- concentration in the solution was 1:1
 (corresponding to the high concentration of OH-). So E1 reaction will occur!
 But I want to find the transition state in the first stage of the SN1 reaction.
 How can do this ?
 Please help me
 Thank you