What is the true definition of coupling constant in nmr spectroscopy?

Answer 1

The distance between the centers of two adjacent peaks in a multiplet is usually constant and is called coupling constant denoted by J

In case of 1s order Splitting above answer is correct. in case of Non-1st Order splitting we should follow the following example

let for AMX(Quartet)

take our hand fingers for spectrum explanation(vomit thumb finger), distance between little finger to middle finger let it 'X' minus distance between showing finger and side finger of little finger let it 'y'.

Now the coupling constant is (X-Y)/2.

Kindly suggest if any mistake or difficulty to understand.

Answer 2

In NMR spectroscopy, a coupling constant is a measure of the interaction between different nuclear spins in a molecule. It provides information about the connectivity and relative arrangement of atoms in a molecule. The value of the coupling constant is influenced by the number of bonds and the dihedral angle between the coupled nuclei.