Around zero field a noticeable drop is observed due to quantum tunneling within that field range. usually given as the distance towards the centroid of the ring , as well as the bending angle Ct-within the first and second excited doublet states. We, therefore, believe that the main relaxation pathway at elevated temperatures follows the idea of thermally assisted quantum tunneling (TA-QTM) via the third excited doublet state. The calculated energy of this state at the given level of theory is 1256.03 K (872.94 cm -1 ) which is in decent agreement with the experimentally observed barrier of 1375 K (955 cm -1 ).