...
  • 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>The Journal of Chemical Physics >Accurate analytic He-H_2 potential energy surface from a greatly expanded set of ab initio energies
【24h】

Accurate analytic He-H_2 potential energy surface from a greatly expanded set of ab initio energies

机译：从头开始的能量极大扩展的集合，精确地分析了He-H_2势能面

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

The interactin potential energy surface (PES) of He-H_2 is of great importance for quantum chemistry as teh simplest test case for interactins between a molecule and a closed-sheel atom It is also required for a detailed understtanding of certain astrophysical processes-namely sollisional excitation and sissociation of H_2 in molecular clouds- at densities too low to be accesible experimentally A new set of 23 703 ab initio energies was computred for He-H_2 gemetries where teh interactin energy was expected to be non-negligible These have an estimated rms"random" error fo ~0.2 mhartree and a systemtic error of ~0.6 mhartree (0.4 kcal/mol) A new sanalytic He_H_2 PES with 112 jparameters was fitted to 20 203 fo these new ab initio energies (and to an additinal 4862 points generated at large secparations) This yhielded an improvement by better than an order of magnitude in the fit to the interactin regions relactive to the best previosu surfaces (which were accurate onloy for near-euilibrium H_2 molecule sizes) This new PES has an rms error of 0.95 mhartree (0.60 kcal/mol) relative to the 14 585 ab initio energies that lie below twice the H_2 dissociation energy and 2.97 mhartree (1.87 kcal/mol) relative to the full set of 20 203 ab initio energies (the fitting procedure used a reduced weight for high energies yielding a weighted rms error of 1.42 mhartree-i.e.,0.89 kcal/mol) These rms errors are comparable to the setimated error in the ab initio energies themselves the conicsl intersection between the grouns state and the first excited state is the largest source of error in the PES.
机译：He-H_2的相互作用素势能面（PES）对于量子化学非常重要，因为它是分子与闭环原子之间相互作用素的最简单测试用例，对于某些天体物理过程（即单亲的）的详细理解也是必需的分子云中H_2的激发和离解-密度太低以致于无法通过实验达到目的对于He-H_2宝石，计算了一组新的23 703从头算起的能量，其中相互作用能被认为是不可忽略的，这些均具有均方根值” 〜0.2 mhartree的“随机”误差和〜0.6 mhartree的系统误差（0.4 kcal / mol）将具有112 para参数的新分析型He_H_2 PES应用于这些新的从头算起的能量20 203（以及在大范围内产生的4486点）分离）与相对于最佳前表面的相互作用蛋白区域的拟合度提高了一个数量级以上H_2分子大小）这种新的PES的均方根误差为0.95 mhartree（0.60 kcal / mol）相对于14 585 ab的初始能量低于H_2离解能的两倍和2.97 mhartree（1.87 kcal / mol）相对于全部一组20 203 ab初始能量（拟合过程对高能量使用了减小的重量，导致加权均方根误差为1.42 mhartree-ie，0.89 kcal / mol）。这些均方根误差与ab初始能量本身的设定误差相当。接地状态和第一激发状态之间的圆锥曲线相交是PES中最大的误差来源。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号