The influence of the quencher concentration on the rate of simple bimolecular reaction: Molecular dynamics study

Abstract

The paper presents the results of large-scale molecular dynamics simulations of the irreversible bimolecular reaction A+B --> C+B for the simple liquid composed of mechanically identical soft spheres. The systems with the total number of molecules corresponding to 10(7)-10(9) are considered. The influence of the concentration of a quencher (B) on the surviving probability of A and the reaction rate is analyzed for a wide range of the concentrations and for two significantly different reduced densities. It is shown that the quencher concentration dependence effect (QCDE) is, in fact, a composition of two QCDE effects: the short-time QCDE that increases the reaction rate and the long-time QCDE that decreases it. The paper also analyzes the influence of the concentration on the steady-state rate constant, k(ss), obtained by integrating the surviving probability. The excess in k(ss) due to finite quencher concentration changes the sign from negative to positive while going from low to high concentrations. Generally, the excess is extremely weak. It attains a 1% level only if the concentration is very high.

Effect of Cathode–Anode Distance on Field Emission Properties for Carbon Nanotube Film Emitters

“…Obtaining quantitative results appeared to be not easy and the first simulations, performed using the standard molecular dynamics method, showed only that for the investigated liquids the QCDE decreased the reaction rate in the long-time limit. Further simulations have been performed by applying the method of prerecorded trajectory of Gorecki [19][20][21], which enabled one to consider chemical systems corresponding to 10 7 -10 9 particles. Many interesting and surprising results have been obtained and analysed [21][22][23].…”

“…Further simulations have been performed by applying the method of prerecorded trajectory of Gorecki [19][20][21], which enabled one to consider chemical systems corresponding to 10 7 -10 9 particles. Many interesting and surprising results have been obtained and analysed [21][22][23]. The most important of the results and the simulation method are presented and discussed in this work.…”

Molecular dynamics study on the influence of quencher concentration on the reaction rate for ionic systems

“…25 The Debye wave number ͑A6͒ is the same for all the systems: k D Х 0.26. Reaction ͑2.1͒ was realized in exactly the same way as for the soft sphere systems and the method of prerecorded trajectory [19][20][21] were applied by translating positions of the particles of the basic N particle system L times in each of x , y , z directions. 15 Assuming = 8 Å and T = 300 K, one obtains z 2 / r Х 0.04 for SS and LDS and 0.08 for SIS.…”

“…The interactions between quenchers were also taken into account in the simulation of Senapati et al 17 First attempt to estimate the excess in k͑t , c͒ ͑denoted by ⌬k͒ was done in 2005. [19][20][21] Many interesting results for liquids, [21][22][23] the Brownian systems, 22,23 and gas 23 have been obtained. [19][20][21] Many interesting results for liquids, [21][22][23] the Brownian systems, 22,23 and gas 23 have been obtained.…”

“…[19][20][21] Many interesting results for liquids, [21][22][23] the Brownian systems, 22,23 and gas 23 have been obtained. 21,22 Very recent simulations 24 have shown that the reason of the positive values are the interactions between B molecules. 21,22 Very recent simulations 24 have shown that the reason of the positive values are the interactions between B molecules.…”