Torsion angles are important paramters for describing the conformaitons of polyatomic
molecules. A torsion angle is defined by the positions of four atoms. Here i, j, k, and l ae
the indices of the four atoms, and the torsion angle, f ijkls defined as the angle between the
planes that contain atoms i, j, k and j, k, l.
f = ArcCosJ u.v N
where u and v are vectors normal to the ijk and jkl planes:
u = rij r jk
v= rlk r jk
|u| and |v| are the magnitudes, and the bond vectors are defined as:
rij ri- r j
rjk r -jr k
rlk r l r k
Where r =iHx , i , i L,ietc.
Calculate teh torsion angle (in both radians and degrees) defined by the four atoms whose positions are
given in the table:
ri = 84.212, 3.319, -9.332