  We demonstrate that the Mpemba paradox arises intrinsically from the release
rate of energy initially stored in the covalent H-O part of the O:H-O bond in
water albeit experimental conditions. Generally, heating raises the energy of a
substance by lengthening and softening all bonds involved. However, the O:H
nonbond in water follows actively the general rule of thermal expansion and
drives the H-O covalent bond to relax oppositely in length and energy because
of the inter-electron-electron pair coupling [J Phys Chem Lett 4, 2565 (2013);
ibid 4, 3238 (2013)]. Heating stores energy into the H-O bond by shortening and
stiffening it. Cooling the water as the source in a refrigerator as a drain,
the H-O bond releases its energy at a rate that depends exponentially on the
initially storage of energy, and therefore, Mpemba effect happens. This effect
is formulated in terms of the relaxation time tau to represent all possible
processes of energy loss. Consistency between predictions and measurements
revealed that the tau drops exponentially intrinsically with the initial
temperature of the water being cooled.
