at the beginning;

"at first he didn't notice anything strange"

ab initio molecular orbital and density functional theory(dft) in conjunction with different basis sets calculations were performed to study the n-h…o blue-shifted hydrogen bond in the hno dimer.

利用分子轨道从头算理论和密度泛函理论结合不同理论基组对于n-h…o蓝移氢键进行了详细的研究。

ab initio dft/b3lyp calculations at 6—31g basis set level were carried out for the possible product radicals of guanine attacked by·oh.

采用密度泛函（dft）理论中b3lyp方法在6—31g基组水平上对鸟嘌呤（g）受羟基自由基进攻形成的各种可能产物自由基进行几何全优化。

the rapid development of modern quantum chemical theory at ab initio level has also led to the rapid development of theoretical study on nonlinear optical properties of molecular materials.

在理论研究方面，由于从头计算量子化学理论方法的迅速发展，使得对分子材料非线性光学性质的理论研究得以迅速发展。

the reaction of f atoms with ·ch2sh radi cal has been studied by using quantum chemistry ab initio and density function theory (dft) calculations along the potential energy surface.

用量子化学从头算和密度泛函理论（dft）对f原子与自由基ch2 sh在势能面上的反应进行了研究。

the efficiency of gene prediction could be improved by ab initio prediction combined with est information.

利用这些特征可以提高特定序列中这三类元件的预测效率。

abeem/mm model and ab initio method has been applied to study the best way of adding one or two water molecules on small water clusters.

本文应用abeem/mm模型和从头计算方法，研究了对小型水分子团簇添加几个水分子的最优方式。

ab initio calculations are performed, using a slab model with 6 atom-layers, to investigate the character of clean surface, surface with vacancy.

利用第一性原理赝势法，采用6层原子层的层晶模型研究了完整铜表面、含空位缺陷表面的性质。

two different symmetric configurations in the electronic structure of propadiene molecule are calculated by adopting pshondo scf full electronic ab initio calculation.

采用pshondo-scf全电子从头计算程序，对丙二烯分子的两种不同对称性构型的电子结构进行计算。

the structure and chemical bonds of 1-fluorosiltrane have been studied by ab initio method.

本文用量子化学从头计算方法研究了1-苯基杂氮硅三环的电子结构和化学键。

to find unknown protein-coding genes, annotation pipelines use a combination of ab initio gene prediction and similarity to experimentally confirmed genes or proteins.

为了找出编码蛋白质的基因，注释流程结合了「从头开始的基因预测方法」和「与已知基因相似性比较」这两种方法。

this kind of molecular material has strong nonlinear optical properties, and its electronic structures and dipole moments are calculated by use of density functional theory on ab initio level.

该分子材料具有较强的非线性光学性质，其分子的电子结构和电偶极矩是在密度泛函理论水平上利用从头计算方法得到的。

the potential energy surface of the reaction of f atom with·ch2oh is studied by ab initio mo method.

用量子化学从头计算法对氟原子与羟亚甲基ch_2oh在势能面上的反应进行了研究。

by now, experimental values of chemical shifts have been very accurate and ab initio methods have also been greatly developed.

目前，化学位移与核自旋偶合常数的实验测量值已经非常精确，量子化学从头算方法也有了较大的进展。

using ab initio method, the minimum energy conformations and netcharge distribution have been studied for h_2cn radical isomers formed by addition ofa h atom (or an electron) to hcn (or hnc) molecule.

用量子化学从头计算法研究了hcn、hnc分子与h原子和电子加成生成的h_2cn自由基异构体的最低总能量构象和凈电荷分布。

ab initio molecular orbital method has been employed, in this paper, to study the mechanism of the hydrolysis of acetylcholine.

本文对乙酰胆堿水解反应历程进行了从头算分子轨道研究。

by using the ab initio molecular dynamics method, we have studied the structural properties of liquid gallium at high temperature and high density.

采用第一性原理分子动力学方法研究了高温下正常密度和高密度液体镓的结构和性质。

the calculation results showed that ab initio had its advantages in the calculating of atom cluster, especially in the aspect of precision and total energy calculation.

计算结果表明：从头计算方法用于原子簇的计算在精度和总能量计算方面有其自身的优势；

these four parameters are calculated by ab initio method in this paper.

本论文针对上述四个重要的参数作了量子力学的从头计算。

the reaction of hno with o radical was investigated by density functional theory(dft)and ab initio methods.

用密度泛函理论（dft）和从头算方法，对hno与o自由基反应进行了研究。

the structure and chemical bonds of 1 phenyl silatrane have been studies by ab initio method.

本文用量子化学从头计算方法研究了1-苯基杂氮硅三环的电子结构和化学键。

the results show that in ab initio method the choice of pseudopotential has great influence, and different basis function leads to different lattice constant in si material.

计算结果表明，在第一性原理计算方法中，赝势的选用和基函数的确定对计算结果起很大影响，不同的基函数对应不同的硅单晶的晶格常数。

allen and co-worker did ab initio calculation to test the adequacy of scf mo calculations for predicting molecular equilibrium geometries.

爱伦及其同事应用从头计算法来考查scfmo计算对于预示分子平衡几何形的适宜性 。

the article elaborates the method of adding pseudo - potential to ab initio calculation to solve problems in multi - electron system.

文章介绍了在从头计算方法中加入赝势来求解多电子体系问题的方法。

we report the young's modulus of a series single-wall carbon nanotubes(armchair type and zigzag type)and bn zigzag type nanotubes on the basis of ab initio theory.

基于第一性原理计算了一系列单壁碳纳米管（椅型、锯齿型）和氮化硼锯齿型纳米管的杨氏模量。

it is very easy to apply this optimization approach to various semi-empirical and ab initio molecular orbital calculation.

该法容易应用到各种半经验的和从头计算量子化学的方法中去。