  The supercooled liquid silicon, modeled by Stillinger-Weber potential, shows
anomalous increase in heat capacity $C_p$, with a maximum $C_p$ value close to
1060 K at zero pressure. We study equilibration and relaxation of the
supercooled SW Si, in the temperature range of 1060 K--1070 K at zero pressure.
We find that as the relaxation of the metastable supercooled liquid phase
initiates, a straight line region (SLR) is formed in cumulative potential
energy distributions. The configurational temperature corresponding to the SLR
is close to 1060 K, which was earlier identified as the freezing temperature of
4-coordinated amorphous network. The SLR is found to be tangential to the
distribution of the metastable liquid phase and thus influences the broadness
of the distribution. As the bath temperature is reduced from 1070 K to 1060 K,
the effective temperature approaches the bath temperature which results in
broadening of the metastable phase distribution. This, in turn, causes an
increase in overall fluctuations of potential energy and hence an increase of
heat capacity. We also find that during initial stages of relaxation,
4-coordinated atoms form 6-membered rings with a chair--like structure and
other structural units that indicate crystallization. Simultaneously a strong
correlation is established between the number of chair-shaped 6-membered rings
and the number of 4-coordinated atoms in the system. This shows that all
properties related to 4-coordinated particles are highly correlated as the SLR
is formed in potential energy distributions and this can be interpreted as a
consequence of `freezing' of amorphous network formed by 4-coordinated
particles.
