activation energy

(redirected from Activation enthalpy)
Also found in: Dictionary, Medical, Encyclopedia.
Related to Activation enthalpy: Energy barrier
Graphic Thesaurus  🔍
Display ON
Animation ON
  • noun

Synonyms for activation energy

the energy that an atomic system must acquire before a process (such as an emission or reaction) can occur

Based on WordNet 3.0, Farlex clipart collection. © 2003-2012 Princeton University, Farlex Inc.
References in periodicals archive ?
Attributes SCP formation Activation energy 37.5 [+ or -] 2 (b) Activation enthalpy (kJ/mol) 73.2 [+ or -] 3 (b) Activation entropy (J/mol x K) -16.88 [+ or -] 4 (a) Attributes Thermal inactivation P Activation energy 42.57 [+ or -] 1.5 (a) 0.025 Activation enthalpy (kJ/mol) 82.47 [+ or -] 2 (a) 0.011 Activation entropy (J/mol x K) -535 [+ or -] 14 (b) 0.0001 Each value is a mean of three replicates.
4, we see that the values of the activation enthalpy display a strong deviation from the zero entropy line, meaning that the distribution of relaxation times is now very wide in enthalpy (or energy), as well as in entropy (or in prefactor).
A third thermal degradation parameter, the activation enthalpy, was obtained from the following equation: E = [DELTA][H.sup.#] - R[T.sub.S].
Table 3: Activation parameters for the corrosion of 6061 Al alloy in 0.5 M sodium hydroxide solution in the presence of MAMT Inhibitor [E.sub.a] [DELTA] [H.sun.a] - [DELTA] [S.sub.a] concentration (kJ mo[l.sup.-1]) (kJ mo[l.sup.-1]) (J mo[l.sup.-1] (ppm) [k.sup.-1]) 0 17.79 15.19 160.98 5 24.70 22.10 143.12 10 24.85 22.25 143.37 25 27.65 25.05 135.06 50 30.83 28.23 125.83 The effect of chemically stable surface active inhibitors is to increase the energy of activation and to decrease the surface area available for corrosion.30 The results in Table 3 indicate that the value of activation energy [E.sub.a], activation enthalpy [DELTA] [H.sub.a], and activation entropy [DELTA] [S.sub.a] are given in Table 3.
Figure 4 presents the OIT activation enthalpy plot of two of the films.
The energy of activated molecules is a kind of triplet consisting mostly of three components: activation enthalpy, activation entropy and free energy of activation [8, 22].
where [DELTA][H.sub.eq.sup.0] is the enthalpy of the equilibrium, [DELTA][] is the apparent enthalpy of activation, and [DELTA][H.sub.prop] is the activation enthalpy of propagation.
This suggests that the activation volume [V.sup.*] and the activation enthalpy [DELTA]H expressed in Eq 6 seem to be the material characteristics of the blend.
We have also extracted from TSC the distribution of the activation enthalpy. Those values have allowed us to identify localized and delocalized movements.
It is shown that activation parameters, like the activation enthalpy and volumes, depend on these stress components only through a linear combination, or "reduced mixed stress," s = u/[Mu] = ([[Sigma].sub.c] + m[[Sigma].sub.n])/[Mu], with [Mu] the shear modulus.
Indeed, if [V.sub.a] is independent of the stress and the temperature, it is possible to relate the activation volume and the activation enthalpy to parameters measured by experiment (10):