x

ab initio

uploads/ab initio.jpg

ab initio 〔拉丁語〕 從開始起。

〔拉丁語〕 從開始起。

ab-

The elastic constants of bcc li , na and fcc al crystals have been evaluated as functions of pressure and temperature by using a new model together with ab initio electronic structure and total - energy calculations . in the model it is considered that the elastic constants of crystals at a given temperature and pressure can be calculated using a conventional density functional method but modified by a new set lattice constants due to the isobaric volumetric thermal expansion when temperature rise from absolute zero to the given one 本文對高壓及有限溫度立方金屬彈性常數的計算方法進行了研究，建立了一種考慮溫度效應的物理模型，基于這個模型和從頭算方法，對典型的立方晶系金屬li 、 na 、 al在高壓及有限溫度(熔點以下溫度)彈性常數進行了計算，取得了與已有實驗結果較好相符的計算結果。

We have calculated one - and two - photon absorption cross sections of the lowest excited states of a series of molecules combined with benzene , stilben , thiophene as center attached with amine , diphenylamine , diethylamine as electron - donor and nitryl as electron - acceptor ; the effects of molecular length , n center and electron - donor on two - photon absorption cross sections have been studied and all calculations have been carried out using the density functional theory at an ab initio level . it is found that the molecular length and the one - photon absorption intensity are quite strongly c orrelated factors , and that a corresponding correlation for the two - photon absorption is decreasing . it is also found that a most crucial role for the two - photon absorption is played by the n center 我們分別以苯、二苯乙烯、噻吩為中心，氨基、二苯氨基和二乙氨基為電子給體，硝基為電子受體組合形成的分子為研究對象，在從頭計算的水平上用密度泛函理論計算了這些分子在低激發態下的單、雙光子吸收強度，重點研究了分子的長度、中心和給體的供電子能力對分子單、雙光子吸收的影響。研究結果表明，分子長度與單光子吸收強度之間有密切關系，而在雙光子吸收中這種關系較弱；中心在雙光子吸收中具有重要的作用；在中心和受體一定的情況下，增加給體的供電子能力，可提高雙光子吸收強度。

At present , the studies on this are mainly focus on the surface geometry structure . little is payed for the electronic structure . in this dissertation , the surface properties of high miller index surface of metals and semiconductors were studies by using the molecular dynamics method , the scattering theoretical method and the ab initio quantum mechanical molecular dynamics simulations 金屬和半導體材料的高密勒指數表面是目前表面科學研究的一個熱點問題，也是值得更進一步研究的問題，目前的研究主要集中在對表面幾何結構的確定，而對表面電子特性的認識幾乎很少涉及，本文根據目前實驗上對一些表面已有的研究結果，在理論上對一些金屬、半導體的高密勒指數表面的表面能和表面電子結構進行了研究。

We review the advantage and disadvantage of the earliest discovered superhard material - diamond in the industrial application . since the calculation results of ab initio pseudpotential method by dr . cohen and dr . liu showed that the bulk modulus and hardness are comparable to or higher than diamond , the worldwide experimental and theoretical research activities on superhard materials especial of - c3n4 have been arising 并介紹了自1989年以來， liu和cohen兩位教授運用第一原理贗勢法計算出? c3n4的彈性模量和結構性能，表明? c3n4具有很大的結合能和大于金剛石的彈性模量及硬度后，在世界各國的研究機構和大學里，掀起了一股對超硬薄膜cnx的研究高潮。

On the basis of one - electron hartree - fock approximation , the extended - ion method and ab initio method have been used to investigate the f center migration between f ~ - layers , br ~ - layers and from f ~ - layer to br ~ - layer . we have calculated the energy barrier of these three f center migrationes and energy of f center , exciton energy . the results of f center and exciton are in good agreement with the experimential data 本文是在單電子hartree - fock近似的基礎上采用擴展離子方法和全電子從頭計算方法，研究了bafbr ： eu ~ ( 2 + )晶格中的f ~ -離子層間的f心遷移， br ~ -層的f心遷移和f ~ -離子與br ~ -離子層間f心遷移過程中的能量勢壘和f心基態、激發態以及激子能量，對于f心和激子的研究結果與實驗符合的很好。

The purpose of studying the structure - activity relationship ( sar ) of vitamin e is to study the difference of the molecular geometry , which has different effect on the reaction activity of the molecule and produce different biological activity . semi - empirical ami and pm3 method and ab initio 3 - 21g methods are applied to optimize the four different geometries of tocopherol in the present work . using the two methods we have obtained some parameters about the biological activity 計算步驟是，先使用hyperchem6構造出各種化合物，用hyperchem自帶的分子力學mm +和polak - ribiere優化方法在目標分子的構象空間中尋找能量相對較低的構象，然后用am1半經驗方法進一步優化其構型，得到一系列能量值，然后利用hyperchem6 . 0其中集成的qsar模塊，計算化合物的qsar參數，其中包括：疏水性參數( logp ) 、分子表面積、總體積、折射率、極化率等參數。

Clause 25 where an obligee brings a suit to enforce its cancellation right pursuant to article 74 of the contract law and petitions the people ' s court for cancellation of the obligor ' s act of waiving its creditor ' s right or transferring its property , the people ' s court shall adjudicate the case to the extent of the amount claimed by the obligee , and if the obligor ' s act is canceled in accordance with the law , such act is invalid ab initio 第二十五條債權人依照合同法第七十四條的規定提起撤銷權訴訟，請求人民法院撤銷債務人放棄債權或轉讓財產的行為，人民法院應當就債權人主張的部分進行審理，依法撤銷的，該行為自始無效。

The vibrational excitation cross - sections of low - energy electron scattering from n2 molecule are studied using the improved body - frame vibrational close - coupling ( bfvcc ) method and quantum scattering potentials including static , exchange and polatization contributions based on ab initio calculations 摘要使用經孫衛國教授改進后的振動密耦合散射方法和基于量子力學從頭計算得到的靜電、交換與極化散射作用勢，研究了低能電子與n2分子的振動激發散射截面。

In this thesis , the rule of electronic structure changes after intercalation and substitution in the layered licoo2 , linio2 and the spinel limn2o4 has been studied by using quantum chemical ab initio and density function theory ( dft ) 本論文運用量子化學從頭計算和密度泛函方法對層狀結構licoo2 、 linio2和尖晶石結構limn2o4材料進行了較為系統的研究，初步探討這些材料在嵌鋰前后電子結構的變化規律以及錳系摻雜材料摻雜離子對其電子結構的影響。

In the second part of the dissertation , we have used the ab initio cluster model approach to study the adsorption of co on the pt - ru alloys surfaces . the calculated equilibrium geometries and vibrational frequencies have been found to be rather in agreement with experimental study 本文還用原子簇模型近似模擬了co在pt - rt二元合金表面的吸附，計算了它在平衡狀態時的結構和振動光譜，發現它們與實驗值極其一致。

Research interest : surface science ; kikuchi electron holography ; electron multiple - scattering techinques ; molecular dynamical simulations ; ab initio total energy calculations ; self - diffusion on metal surfaces ; dissociative adsorption of h2 on metal surfaces 研究興趣:表面科學，電子全像術，電子多重散射分析理論技術，分子動力學模擬，第一原則總能量計算，表面原子動態學，氫分子的解離吸附。

The ab initio calcu1ation by selecting cluster mode1 with different size showed that with the decrement of model size the quantum - sized effect was more prominence , the energy distance was bigger near fermi energy , the energy schism was also more obvious 選取不同尺度的簇模型從頭計算表明，隨著尺度的減小量子尺寸效應越發顯著，費米能級附近的能級間隔變大，能級分立現象更加明顯。

The structure and energy level of the al clusters include 2 atoms to to 7atoms was calculated with ab initio method . discrete energy levels were found in the clusters , which is different from the energy level distribution of bulk materials 計算方法是采用gaussia98程序的b3lyp的方法和全電子的基函數6 - 311 + g * ，對al2 ? al7小團簇的結構和能級進行了abinitio計算。

The hybrid density functional theory at ab initio level was applied to study solvent effects on geometrical structures , charge distribution , and solvatochromic shifts of 4 - nitro - buta - 1 , 3 - dienylamine molecule 摘要在從頭計算的水平上，利用雜化密度泛函理論研究了溶劑對4 -硝基1 , 3 -丁二烯基胺分子的幾何結構、分子內的電荷分布和電荷轉移態的能量漂移的影響。

The following results have been concluded : ( a ) ab initio has its advantages in the calculating of atom cluster containing transition metal , especially in precision and total energy calculations 結果表明： ( 1 )從頭計算方法在用于原子簇的計算中有其自身的優勢，尤其是在精度和總能量計算方面。

Our dynamic calculation is carried out on a recent ab initio potential energy surface ( pes ) of jordan and gilbert . the tdwp method also is employed as a computational tool 然后在從頭計算法得到的解析勢能面( jordanandgilbert )上，采用含時波包法進行了量子計算。

These data sets were used to evaluate five ab initio gene prediction programs : ricehmm , glimmerr , genemark , fgensh and bgf 用這兩個測試數據集合評估了5個在水稻基因組中預測基因的程序： ricehmm glimmerr genemark fgenesh和我們自己編寫的bgf 。

Theoretical investigations were performed to explore the electronic structure and optical properties of fluorescein using zindo , ab initio and dft methods 摘要用zindo 、從頭算和密度泛函理論方法研究熒光素及其衍生物的電子結構和光譜性質。

Theoretical investigations were performed to explore the electronic structure and optical properties of fluorescein using zindo , ab initio and dft methods 用zindo 、從頭算和密度泛函理論方法研究熒光素及其衍生物的電子結構和光譜性質。