Dear all,

 

I am following Bruce’s video presentation on the Artemis case of FeS₂, and have a beginner’s question here.

 

There is a configuration of    S₁ ---- Fe ---- S₂ .

 

In order to use the existing sigma^2 defined for single scattering path of [Fe – S], Bruce applied linear combination for the following paths:

 

Fe ---- S₁ ---- S₂ ---- Fe         Sigma^2 of this path = sigma^2 [Fe – S] *2

Fe ---- S₁ ---- Fe ---- S₂ ---- Fe   Sigma^2 of this path = sigma^2[Fe – S) *2

Fe ---- S₁---- Fe ---- S₁ ---- Fe   Sigma^2 of this path = sigma^2 [Fe – S] *4

 

Hence the question is, why the third path multiplies 4 while the other two paths multiply 2? For me they should all be 2.

 

Thanks.

 

Regards,

Zhipeng