Michalik V, Begusová M, Bigildeev E A
Nuclear Physics Institute, Radiation Dosimetry Department, Na Truhlárce, Prague, Czech Republic.
Radiat Res. 1998 Mar;149(3):224-36.
A computer-aided stochastic model of the radiolysis of liquid water has been developed. It is based on Monte Carlo simulation of charged-particle tracks, a random-flight method to simulate diffusion of species and the Debye-Smoluchowski theory of reactions between radicals. The model takes into account the formation of ionizations, excitations and subexcitation electrons at the physical stage. The corresponding initial yields at approximately 1 fs were found to be G(ion) = 4.37, G(exc) = 2.81 and G(e-sub) = 4.38. The energy spectrum of subexcitation electrons has been calculated. Autoionizations and dissociations of excited molecules, hole migration, electron thermalization, geminate recombination and the cage effect are considered at the physico-chemical stage. The mean thermalization distance of subexcitation electrons is 24.5 nm. The initial yields of e(aq)-, H+, OH, H, H2 and O are 4.89, 4.86, 5.96, 1.10, 0.15 and 0.15, respectively. The reactions between radicals and products as well as their diffusion are simulated at the chemical stage. The decay kinetics of the most important radicals is reported together with the time evolution of the most important reactions. The yields of the reactive radicals, e(aq)-, H+, OH, H and OH-, at 1 ps are 4.84, 4.85, 5.87, 1.09 and 0.0, respectively. The respective steady-state yields at 10 micros are 2.70, 3.58, 2.89, 1.17 and 0.79. The yields of molecular products, H2O2 and H2, are 0.73 and 0.47 at 10 micros. The concentration-dependent yields of e(aq)-, OH and H2O2 are calculated in three different aqueous solutions. The predictions of the model agree fairly well with experimental data.
已开发出一种液态水辐射分解的计算机辅助随机模型。它基于带电粒子轨迹的蒙特卡罗模拟、一种模拟物种扩散的随机飞行方法以及自由基之间反应的德拜 - 斯莫卢霍夫斯基理论。该模型在物理阶段考虑了电离、激发和亚激发电子的形成。发现大约在1飞秒时相应的初始产额为G(离子)=4.37、G(激发)=2.81和G(亚激发电子)=4.38。计算了亚激发电子的能谱。在物理化学阶段考虑了激发分子的自电离和解离、空穴迁移、电子热化、双分子复合和笼效应。亚激发电子的平均热化距离为24.5纳米。水合电子（e(aq)-）、氢离子（H+）、氢氧根离子（OH）、氢原子（H）、氢气（H2）和氧气（O）的初始产额分别为4.89、4.86、5.96、1.10、0.15和0.15。在化学阶段模拟了自由基与产物之间的反应及其扩散。报告了最重要自由基的衰变动力学以及最重要反应的时间演化。在1皮秒时，活性自由基水合电子（e(aq)-）、氢离子（H+）、氢氧根离子（OH）、氢原子（H）和氢氧根离子（OH-）的产额分别为4.84、4.85、5.87、1.09和0.0。在10微秒时各自的稳态产额分别为2.70、3.58、2.89、1.17和0.79。在10微秒时分子产物过氧化氢（H2O2）和氢气（H2）的产额分别为0.73和0.47。计算了三种不同水溶液中水合电子（e(aq)-）、氢氧根离子（OH）和过氧化氢（H2O2）的浓度依赖性产额。该模型的预测与实验数据相当吻合。
