- #1

Dibyajyoti Das

- 1

- 0

**1.Hi,**

Need to find fourth point S coordinate, given the below:

1. coordinates of P,Q,R,

2. torsion angle between PQR and QRS,

3. the bond length RS and

4. bond angle QRS.

Can anybody give me the way out?

Need to find fourth point S coordinate, given the below:

1. coordinates of P,Q,R,

2. torsion angle between PQR and QRS,

3. the bond length RS and

4. bond angle QRS.

Can anybody give me the way out?

**2. Equaltions for Torsion angles**

b1=PQ

b2=QR

b3=RS

where PQ,QR and RS are all vectors,

n1=⟨b1×b2⟩ and n2=⟨b2×b3⟩

ϕ=cos

b1=PQ

b2=QR

b3=RS

where PQ,QR and RS are all vectors,

n1=⟨b1×b2⟩ and n2=⟨b2×b3⟩

ϕ=cos

^{−1}(n1.n2 /(∥n| ∥m∥)...(eqn A)**3. The torson angle can be found easily given four points. However since there are three unknowns x,y,z of point S, its not possible here**

Last edited: