首页 > 最新文献

arXiv: Chemical Physics最新文献

英文 中文
Interpolated Wave Functions for Nonadiabatic Simulations with the Fixed-Node Quantum Monte Carlo Method 用固定节点量子蒙特卡罗方法进行非绝热模拟的内插波函数
Pub Date : 2016-07-10 DOI: 10.1021/BK-2016-1234.CH003
N. Tubman, Yubo Yang, S. Hammes‐Schiffer, D. Ceperley
Simulating nonadiabatic effects with many-body wave function approaches is an open field with many challenges. Recent interest has been driven by new algorithmic developments and improved theoretical understanding of properties unique to electron-ion wave functions. Fixed-node diffusion Monte Caro is one technique that has shown promising results for simulating electron-ion systems. In particular, we focus on the CH molecule for which previous results suggested a relatively significant contribution to the energy from nonadiabatic effects. We propose a new wave function ansatz for diatomic systems which involves interpolating the determinant coefficients calculated from configuration interaction methods. We find this to be an improvement beyond previous wave function forms that have been considered. The calculated nonadiabatic contribution to the energy in the CH molecule is reduced compared to our previous results, but still remains the largest among the molecules under consideration.
用多体波函数方法模拟非绝热效应是一个充满挑战的开放领域。最近的兴趣是由新的算法发展和对电子-离子波函数独特性质的改进的理论理解所驱动的。固定节点扩散蒙特卡罗是一种在模拟电子-离子系统方面显示出良好结果的技术。我们特别关注CH分子,先前的结果表明,CH分子对非绝热效应的能量贡献相对显著。本文提出了一种新的双原子系统的波函数分析方法,该方法将由组态相互作用方法计算出的决定系数进行插值。我们发现这比以前所考虑的波函数形式有所改进。与我们之前的结果相比,计算出的CH分子的非绝热能量贡献减少了,但仍然是所考虑的分子中最大的。
{"title":"Interpolated Wave Functions for Nonadiabatic Simulations with the Fixed-Node Quantum Monte Carlo Method","authors":"N. Tubman, Yubo Yang, S. Hammes‐Schiffer, D. Ceperley","doi":"10.1021/BK-2016-1234.CH003","DOIUrl":"https://doi.org/10.1021/BK-2016-1234.CH003","url":null,"abstract":"Simulating nonadiabatic effects with many-body wave function approaches is an open field with many challenges. Recent interest has been driven by new algorithmic developments and improved theoretical understanding of properties unique to electron-ion wave functions. Fixed-node diffusion Monte Caro is one technique that has shown promising results for simulating electron-ion systems. In particular, we focus on the CH molecule for which previous results suggested a relatively significant contribution to the energy from nonadiabatic effects. We propose a new wave function ansatz for diatomic systems which involves interpolating the determinant coefficients calculated from configuration interaction methods. We find this to be an improvement beyond previous wave function forms that have been considered. The calculated nonadiabatic contribution to the energy in the CH molecule is reduced compared to our previous results, but still remains the largest among the molecules under consideration.","PeriodicalId":8439,"journal":{"name":"arXiv: Chemical Physics","volume":"74 1","pages":"47-61"},"PeriodicalIF":0.0,"publicationDate":"2016-07-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79014823","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 1
Accurate Non-adiabatic Quantum Dynamics from Pseudospectral Sampling of Time-dependent Gaussian Basis Sets 基于时变高斯基集伪谱采样的精确非绝热量子动力学
Pub Date : 2016-06-20 DOI: 10.1063/1.4959872
C. Heaps, D. Mazziotti
Quantum molecular dynamics requires an accurate representation of the molecular potential energy surface from a minimal number of electronic structure calculations, particularly for nonadiabatic dynamics where excited states are required. In this paper, we employ pseudospectral sampling of time-dependent Gaussian basis functions for the simulation of non-adiabatic dynamics. Unlike other methods, the pseudospectral Gaussian molecular dynamics tests the Schrodinger equation with $N$ Dirac delta functions located at the centers of the Gaussian functions reducing the scaling of potential energy evaluations from $mathcal{O}(N^2)$ to $mathcal{O}(N)$. By projecting the Gaussian basis onto discrete points in space, the method is capable of efficiently and quantitatively describing nonadiabatic population transfer and intra-surface quantum coherence. We investigate three model systems; the photodissociation of three coupled Morse oscillators, the bound state dynamics of two coupled Morse oscillators, and a two-dimensional model for collinear triatomic vibrational dynamics. In all cases, the pseudospectral Gaussian method is in quantitative agreement with numerically exact calculations. The results are promising for nonadiabatic molecular dynamics in molecular systems where strongly correlated ground or excited states require expensive electronic structure calculations.
量子分子动力学需要从最少数量的电子结构计算中精确地表示分子势能面,特别是对于需要激发态的非绝热动力学。本文采用时变高斯基函数的伪谱采样来模拟非绝热动力学。与其他方法不同的是,伪谱高斯分子动力学在高斯函数的中心使用$N$狄拉克函数来测试薛定谔方程,将势能评估的标度从$mathcal{O}(N^2)$降低到$mathcal{O}(N)$。该方法通过将高斯基投影到空间离散点上,能够有效定量地描述非绝热种群迁移和表面内量子相干性。我们研究了三个模型系统;三个耦合莫尔斯振子的光解,两个耦合莫尔斯振子的束缚态动力学,以及共线三原子振动动力学的二维模型。在所有情况下,伪谱高斯方法在定量上与数值精确计算是一致的。这一结果在分子系统的非绝热分子动力学中是有希望的,在这些系统中,强相关的基态或激发态需要昂贵的电子结构计算。
{"title":"Accurate Non-adiabatic Quantum Dynamics from Pseudospectral Sampling of Time-dependent Gaussian Basis Sets","authors":"C. Heaps, D. Mazziotti","doi":"10.1063/1.4959872","DOIUrl":"https://doi.org/10.1063/1.4959872","url":null,"abstract":"Quantum molecular dynamics requires an accurate representation of the molecular potential energy surface from a minimal number of electronic structure calculations, particularly for nonadiabatic dynamics where excited states are required. In this paper, we employ pseudospectral sampling of time-dependent Gaussian basis functions for the simulation of non-adiabatic dynamics. Unlike other methods, the pseudospectral Gaussian molecular dynamics tests the Schrodinger equation with $N$ Dirac delta functions located at the centers of the Gaussian functions reducing the scaling of potential energy evaluations from $mathcal{O}(N^2)$ to $mathcal{O}(N)$. By projecting the Gaussian basis onto discrete points in space, the method is capable of efficiently and quantitatively describing nonadiabatic population transfer and intra-surface quantum coherence. We investigate three model systems; the photodissociation of three coupled Morse oscillators, the bound state dynamics of two coupled Morse oscillators, and a two-dimensional model for collinear triatomic vibrational dynamics. In all cases, the pseudospectral Gaussian method is in quantitative agreement with numerically exact calculations. The results are promising for nonadiabatic molecular dynamics in molecular systems where strongly correlated ground or excited states require expensive electronic structure calculations.","PeriodicalId":8439,"journal":{"name":"arXiv: Chemical Physics","volume":"49 3 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2016-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76646882","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 4
Electronic friction near metal surfaces: a case where molecule-metal couplings depend on nuclear coordinates 金属表面附近的电子摩擦:分子-金属耦合依赖于核坐标的一种情况
Pub Date : 2016-06-20 DOI: 10.1063/1.4965823
Wenjie Dou, Joseph E. Subotnik
We derive an explicit form for the electronic friction as felt by a molecule near a metal surface for the general case that molecule-metal couplings depend on nuclear coordinates. Our work generalizes a previous study by von Oppen et al [Beilstein Journal of Nanotechnology, 3, 144, 2012], where we now go beyond the Condon approximation (i.e. molecule-metal couplings are not held constant). Using a non-equilibrium Green's function formalism in the adiabatic limit, we show that fluctuating metal-molecule couplings lead to new frictional damping terms and random forces, plus a correction to the potential of mean force. Numerical tests are performed and compared with a modified classical master equation; our results indicate that violating the Condon approximation can have a large effect on dynamics.
对于分子-金属耦合依赖于核坐标的一般情况,我们导出了分子在金属表面附近所感受到的电子摩擦的显式形式。我们的工作概括了von Oppen等人之前的研究[Beilstein Journal of Nanotechnology, 3,144, 2012],我们现在超越了Condon近似(即分子-金属耦合不保持恒定)。在绝热极限下使用非平衡格林函数形式,我们表明波动的金属-分子耦合导致新的摩擦阻尼项和随机力,加上对平均力势的修正。进行了数值试验,并与修正后的经典主方程进行了比较;我们的结果表明,违反康登近似会对动力学产生很大的影响。
{"title":"Electronic friction near metal surfaces: a case where molecule-metal couplings depend on nuclear coordinates","authors":"Wenjie Dou, Joseph E. Subotnik","doi":"10.1063/1.4965823","DOIUrl":"https://doi.org/10.1063/1.4965823","url":null,"abstract":"We derive an explicit form for the electronic friction as felt by a molecule near a metal surface for the general case that molecule-metal couplings depend on nuclear coordinates. Our work generalizes a previous study by von Oppen et al [Beilstein Journal of Nanotechnology, 3, 144, 2012], where we now go beyond the Condon approximation (i.e. molecule-metal couplings are not held constant). Using a non-equilibrium Green's function formalism in the adiabatic limit, we show that fluctuating metal-molecule couplings lead to new frictional damping terms and random forces, plus a correction to the potential of mean force. Numerical tests are performed and compared with a modified classical master equation; our results indicate that violating the Condon approximation can have a large effect on dynamics.","PeriodicalId":8439,"journal":{"name":"arXiv: Chemical Physics","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2016-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76316588","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 32
On the mass of atoms in molecules: Beyond the Born-Oppenheimer approximation 论分子中原子的质量:超越玻恩-奥本海默近似
Pub Date : 2016-05-13 DOI: 10.1103/PhysRevX.7.031035
A. Scherrer, F. Agostini, D. Sebastiani, E. Gross, R. Vuilleumier
Describing the dynamics of nuclei in molecules requires a potential energy surface, which is traditionally provided by the Born-Oppenheimer or adiabatic approximation. However, we also need to assign masses to the nuclei. There, the Born-Oppenheimer picture does not account for the inertia of the electrons and only bare nuclear masses are considered. Nowadays, experimental accuracy challenges the theoretical predictions of rotational and vibrational spectra and requires to include the participation of electrons in the internal motion of the molecule. More than 80 years after the original work of Born and Oppenheimer, this issue still is not solved in general. Here, we present a theoretical and numerical framework to address this problem in a general and rigorous way. Starting from the exact factorization of the electron-nuclear wave function, we include electronic effects beyond the Born-Oppenheimer regime in a perturbative way via position-dependent corrections to the bare nuclear masses. This maintains an adiabatic-like point of view: the nuclear degrees of freedom feel the presence of the electrons via a single potential energy surface, whereas the inertia of electrons is accounted for and the total mass of the system is recovered. This constitutes a general framework for describing the mass acquired by slow degrees of freedom due to the inertia of light, bounded particles. We illustrate it with a model of proton transfer, where the light particle is the proton, and with corrections to the vibrational spectra of molecules. Inclusion of the light particle inertia allows to gain orders of magnitude in accuracy.
描述分子中原子核的动力学需要一个势能面,这是传统上由玻恩-奥本海默近似或绝热近似提供的。然而,我们还需要给原子核分配质量。在那里,玻恩-奥本海默图没有考虑电子的惯性,只考虑裸核质量。目前,实验精度对旋转和振动光谱的理论预测提出了挑战,并要求包括电子在分子内部运动中的参与。在伯恩和奥本海默最初的工作80多年后,这个问题仍然没有得到普遍解决。在这里,我们提出了一个理论和数值框架,以一般和严格的方式解决这个问题。从电子-核波函数的精确分解开始,我们通过对裸核质量的位置相关修正,以微扰的方式包括了Born-Oppenheimer状态以外的电子效应。这维持了一个类似绝热的观点:核自由度通过单个势能表面感受电子的存在,而电子的惯性被考虑在内,系统的总质量被恢复。这就构成了描述由于光和有界粒子的惯性而产生的慢自由度所获得的质量的一般框架。我们用质子转移模型来说明这一点,其中光粒子是质子,并对分子的振动谱进行了修正。包含光粒子的惯性可以使精度提高几个数量级。
{"title":"On the mass of atoms in molecules: Beyond the Born-Oppenheimer approximation","authors":"A. Scherrer, F. Agostini, D. Sebastiani, E. Gross, R. Vuilleumier","doi":"10.1103/PhysRevX.7.031035","DOIUrl":"https://doi.org/10.1103/PhysRevX.7.031035","url":null,"abstract":"Describing the dynamics of nuclei in molecules requires a potential energy surface, which is traditionally provided by the Born-Oppenheimer or adiabatic approximation. However, we also need to assign masses to the nuclei. There, the Born-Oppenheimer picture does not account for the inertia of the electrons and only bare nuclear masses are considered. Nowadays, experimental accuracy challenges the theoretical predictions of rotational and vibrational spectra and requires to include the participation of electrons in the internal motion of the molecule. More than 80 years after the original work of Born and Oppenheimer, this issue still is not solved in general. Here, we present a theoretical and numerical framework to address this problem in a general and rigorous way. Starting from the exact factorization of the electron-nuclear wave function, we include electronic effects beyond the Born-Oppenheimer regime in a perturbative way via position-dependent corrections to the bare nuclear masses. This maintains an adiabatic-like point of view: the nuclear degrees of freedom feel the presence of the electrons via a single potential energy surface, whereas the inertia of electrons is accounted for and the total mass of the system is recovered. This constitutes a general framework for describing the mass acquired by slow degrees of freedom due to the inertia of light, bounded particles. We illustrate it with a model of proton transfer, where the light particle is the proton, and with corrections to the vibrational spectra of molecules. Inclusion of the light particle inertia allows to gain orders of magnitude in accuracy.","PeriodicalId":8439,"journal":{"name":"arXiv: Chemical Physics","volume":"6 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2016-05-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91325339","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 35
Linear-scaling generation of potential energy surfaces using a double incremental expansion 使用双增量展开的势能曲面的线性缩放生成
Pub Date : 2016-05-05 DOI: 10.1063/1.4960189
Carolin Konig, O. Christiansen
We present a combination of the incremental expansion of potential energy surfaces (PESs), known as n-mode expansion, with the incremental evaluation of the electronic energy in a many-body approach. The application of semi-local coordinates in this context allows the generation of PESs in a very cost-efficient way. For this, we employ the recently introduced flexible adaptation of local coordinates of nuclei (FALCON) coordinates. By introducing an additional transformation step, concerning only a fraction of the vibrational degrees of freedom, we can achieve linear scaling of the accumulated cost of the single point calculations required in the PES generation. Numerical examples of these double incremental approaches for oligo-phenyl examples show fast convergence with respect to the maximum number of simultaneously treated fragments and only a modest error introduced by the additional transformation step. The approach, presented here, represents a major step towards the applicability of vibrational wave function methods to sizable, covalently bound systems.
我们提出了势能面(PESs)的增量扩展,即n模扩展,与多体方法中电子能量的增量评估相结合。在这种情况下,半局部坐标的应用允许以一种非常经济有效的方式产生ps。为此,我们采用了最近引入的核局部坐标的灵活自适应(FALCON)坐标。通过引入一个额外的变换步骤,只涉及振动自由度的一小部分,我们可以实现PES生成所需的单点计算累积成本的线性缩放。对于低聚苯基的例子,这些双增量方法的数值例子表明,相对于同时处理的片段的最大数量,这些方法的收敛速度很快,并且仅由额外的转换步骤引入了适度的误差。该方法,在这里提出,代表了一个重要的一步,振动波函数方法适用于相当大的,共价结合的系统。
{"title":"Linear-scaling generation of potential energy surfaces using a double incremental expansion","authors":"Carolin Konig, O. Christiansen","doi":"10.1063/1.4960189","DOIUrl":"https://doi.org/10.1063/1.4960189","url":null,"abstract":"We present a combination of the incremental expansion of potential energy surfaces (PESs), known as n-mode expansion, with the incremental evaluation of the electronic energy in a many-body approach. The application of semi-local coordinates in this context allows the generation of PESs in a very cost-efficient way. For this, we employ the recently introduced flexible adaptation of local coordinates of nuclei (FALCON) coordinates. By introducing an additional transformation step, concerning only a fraction of the vibrational degrees of freedom, we can achieve linear scaling of the accumulated cost of the single point calculations required in the PES generation. Numerical examples of these double incremental approaches for oligo-phenyl examples show fast convergence with respect to the maximum number of simultaneously treated fragments and only a modest error introduced by the additional transformation step. The approach, presented here, represents a major step towards the applicability of vibrational wave function methods to sizable, covalently bound systems.","PeriodicalId":8439,"journal":{"name":"arXiv: Chemical Physics","volume":"16 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2016-05-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89258760","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 40
Electron Transfer Pathway Analysis in Bacterial Photosynthetic Reaction Center 细菌光合反应中心电子传递途径分析
Pub Date : 2016-04-07 DOI: 10.1007/978-4-431-55357-1_39
Hirotaka Kitoh-Nishioka, K. Ando
{"title":"Electron Transfer Pathway Analysis in Bacterial Photosynthetic Reaction Center","authors":"Hirotaka Kitoh-Nishioka, K. Ando","doi":"10.1007/978-4-431-55357-1_39","DOIUrl":"https://doi.org/10.1007/978-4-431-55357-1_39","url":null,"abstract":"","PeriodicalId":8439,"journal":{"name":"arXiv: Chemical Physics","volume":"35 1","pages":"657-673"},"PeriodicalIF":0.0,"publicationDate":"2016-04-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83388559","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Solar water splitting: efficiency discussion 太阳能水分解:效率讨论
Pub Date : 2016-04-05 DOI: 10.1016/J.IJHYDENE.2016.05.079
J. Juodkazytė, G. Seniutinas, B. Šebeka, I. Savickaja, T. Malinauskas, K. Badokas, K. Juodkazis, S. Juodkazis
{"title":"Solar water splitting: efficiency discussion","authors":"J. Juodkazytė, G. Seniutinas, B. Šebeka, I. Savickaja, T. Malinauskas, K. Badokas, K. Juodkazis, S. Juodkazis","doi":"10.1016/J.IJHYDENE.2016.05.079","DOIUrl":"https://doi.org/10.1016/J.IJHYDENE.2016.05.079","url":null,"abstract":"","PeriodicalId":8439,"journal":{"name":"arXiv: Chemical Physics","volume":"62 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2016-04-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73840357","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 35
Localization of the valence electron of endohedrally confined hydrogen, lithium and sodium in fullerene cages 富勒烯笼中内源性限制氢、锂和钠的价电子定位
Pub Date : 2016-03-08 DOI: 10.1142/S0217979216500557
E. Cuestas, P. Serra
The localization of the valence electron of $H$, $Li$ and $Na$ atoms enclosed by three different fullerene molecules is studied. The structure of the fullerene molecules is used to calculate the equilibrium position of the endohedrally atom as the minimum of the classical $(N+1)$-body Lennard-Jones potential. Once the position of the guest atom is determined, the fullerene cavity is modeled by a short range attractive shell according to molecule symmetry, and the enclosed atom is modeled by an effective one-electron potential. In order to examine whether the endohedral compound is formed by a neutral atom inside a neutral fullerene molecule $X@C_{N}$ or if the valence electron of the encapsulated atom localizes in the fullerene giving rise to a state with the form $X^{+}@C_{N}^{-}$, we analyze the electronic density, the projections onto free atomic states, and the weights of partial angular waves.
研究了被三种不同的富勒烯分子包围的H$、Li$和Na$原子的价电子定位。富勒烯分子的结构被用来计算内质原子的平衡位置,作为经典的$(N+1)$体Lennard-Jones势的最小值。一旦确定了客体原子的位置,根据分子对称性,用短程吸引壳层来模拟富勒烯空腔,用有效单电子势来模拟被封闭的原子。为了检验内嵌式化合物是由中性的富勒烯分子$X@C_{N}$内部的中性原子形成的,还是被包裹的原子的价电子定位在富勒烯中形成了形式为$X^{+}@C_{N}^{-}$的状态,我们分析了电子密度、在自由原子状态上的投影和部分角波的质量。
{"title":"Localization of the valence electron of endohedrally confined hydrogen, lithium and sodium in fullerene cages","authors":"E. Cuestas, P. Serra","doi":"10.1142/S0217979216500557","DOIUrl":"https://doi.org/10.1142/S0217979216500557","url":null,"abstract":"The localization of the valence electron of $H$, $Li$ and $Na$ atoms enclosed by three different fullerene molecules is studied. The structure of the fullerene molecules is used to calculate the equilibrium position of the endohedrally atom as the minimum of the classical $(N+1)$-body Lennard-Jones potential. Once the position of the guest atom is determined, the fullerene cavity is modeled by a short range attractive shell according to molecule symmetry, and the enclosed atom is modeled by an effective one-electron potential. In order to examine whether the endohedral compound is formed by a neutral atom inside a neutral fullerene molecule $X@C_{N}$ or if the valence electron of the encapsulated atom localizes in the fullerene giving rise to a state with the form $X^{+}@C_{N}^{-}$, we analyze the electronic density, the projections onto free atomic states, and the weights of partial angular waves.","PeriodicalId":8439,"journal":{"name":"arXiv: Chemical Physics","volume":"38 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2016-03-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83162833","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 4
Electronic and Optical Properties of the Narrowest Armchair Graphene Nanoribbons Studied by Density Functional Methods 用密度泛函方法研究最窄扶手椅石墨烯纳米带的电子和光学性质
Pub Date : 2016-01-16 DOI: 10.1071/CH16187
Chia-Nan Yeh, Pei-Yin Lee, Jeng-Da Chai
In the present study, a series of planar poly(p-phenylene) (PPP) oligomers with n phenyl rings (n = 1 - 20), designated as n-PP, are taken as finite-size models of the narrowest armchair graphene nanoribbons with hydrogen passivation. The singlet-triplet energy gap, vertical ionization potential, vertical electron affinity, fundamental gap, optical gap, and exciton binding energy of n-PP are calculated using Kohn-Sham density functional theory and time-dependent density functional theory with various exchange-correlation density functionals. The ground state of n-PP is shown to be singlet for all the chain lengths studied. In contrast to the lowest singlet state (i.e., the ground state), the lowest triplet state and the ground states of the cation and anion of n-PP are found to exhibit some multi-reference character. Overall, the electronic and optical properties of n-PP obtained from the omegaB97 and omegaB97X functionals are in excellent agreement with the available experimental data.
在本研究中,一系列具有n苯基环(n = 1 - 20)的平面聚(对苯)(PPP)低聚物,被命名为n- pp,作为氢钝化的最窄扶手椅石墨烯纳米带的有限尺寸模型。利用Kohn-Sham密度泛函理论和时变密度泛函理论计算了n-PP的单重态-三重态能隙、垂直电离势、垂直电子亲和、基态隙、光学隙和激子结合能。n-PP的基态在研究的所有链长中均为单线态。与最低单重态(即基态)相比,n-PP的最低三重态以及正离子和阴离子的基态表现出一些多参考特征。总的来说,从omegaB97和omegaB97X官能团获得的n-PP的电子和光学性质与现有的实验数据非常一致。
{"title":"Electronic and Optical Properties of the Narrowest Armchair Graphene Nanoribbons Studied by Density Functional Methods","authors":"Chia-Nan Yeh, Pei-Yin Lee, Jeng-Da Chai","doi":"10.1071/CH16187","DOIUrl":"https://doi.org/10.1071/CH16187","url":null,"abstract":"In the present study, a series of planar poly(p-phenylene) (PPP) oligomers with n phenyl rings (n = 1 - 20), designated as n-PP, are taken as finite-size models of the narrowest armchair graphene nanoribbons with hydrogen passivation. The singlet-triplet energy gap, vertical ionization potential, vertical electron affinity, fundamental gap, optical gap, and exciton binding energy of n-PP are calculated using Kohn-Sham density functional theory and time-dependent density functional theory with various exchange-correlation density functionals. The ground state of n-PP is shown to be singlet for all the chain lengths studied. In contrast to the lowest singlet state (i.e., the ground state), the lowest triplet state and the ground states of the cation and anion of n-PP are found to exhibit some multi-reference character. Overall, the electronic and optical properties of n-PP obtained from the omegaB97 and omegaB97X functionals are in excellent agreement with the available experimental data.","PeriodicalId":8439,"journal":{"name":"arXiv: Chemical Physics","volume":"7 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2016-01-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85477914","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 9
Interfacial Thermal Conductance of Thiolate-Protected Gold Nanospheres 硫代酸保护金纳米球的界面热导率
Pub Date : 2016-01-13 DOI: 10.1063/1.4939956
Kelsey M. Stocker, Suzanne M. Neidhart, J. D. Gezelter
Molecular dynamics simulations of thiolate-protected and solvated gold nanoparticles were carried out in the presence of a non-equilibrium heat flux between the solvent and the core of the particle. The interfacial thermal conductance ($G$) was computed for these interfaces, and the behavior of the thermal conductance was studied as a function of particle size, ligand flexibility, and ligand chain length. In all cases, thermal conductance of the ligand-protected particles was higher than the bare metal-solvent interface. A number of mechanisms for the enhanced conductance were investigated, including thiolate-driven corrugation of the metal surface, solvent ordering at the interface, solvent-ligand interpenetration, and ligand ordering relative to the particle surface. Only the smallest particles exhibited significant corrugation. All ligands permitted substantial solvent-ligand interpenetration, and ligand chain length has a significant influence on the orientational ordering of interfacial solvent. Solvent-ligand vibrational overlap, particularly in the low frequency range ($< 80 mathrm{cm}^{-1}$) was significantly altered by ligand rigidity, and had direct influence on the interfacial thermal conductance.
在溶剂和粒子核心之间存在非平衡热流密度的情况下,对硫酸盐保护和溶剂化的金纳米颗粒进行了分子动力学模拟。计算了这些界面的界面热导(G$),并研究了热导随粒径、配体柔韧性和配体链长度的变化规律。在所有情况下,配体保护颗粒的热导率都高于裸金属-溶剂界面。研究了许多增强电导的机制,包括硫酸盐驱动的金属表面波纹,界面上的溶剂有序,溶剂-配体互渗,以及相对于颗粒表面的配体有序。只有最小的颗粒表现出明显的波纹。所有配体都允许大量的溶剂-配体互穿,配体链长度对界面溶剂的取向顺序有显著影响。溶剂-配体的振动重叠,特别是在低频范围内($< 80 mathm {cm}^{-1}$),受到配体刚度的显著影响,并直接影响界面热导率。
{"title":"Interfacial Thermal Conductance of Thiolate-Protected Gold Nanospheres","authors":"Kelsey M. Stocker, Suzanne M. Neidhart, J. D. Gezelter","doi":"10.1063/1.4939956","DOIUrl":"https://doi.org/10.1063/1.4939956","url":null,"abstract":"Molecular dynamics simulations of thiolate-protected and solvated gold nanoparticles were carried out in the presence of a non-equilibrium heat flux between the solvent and the core of the particle. The interfacial thermal conductance ($G$) was computed for these interfaces, and the behavior of the thermal conductance was studied as a function of particle size, ligand flexibility, and ligand chain length. In all cases, thermal conductance of the ligand-protected particles was higher than the bare metal-solvent interface. A number of mechanisms for the enhanced conductance were investigated, including thiolate-driven corrugation of the metal surface, solvent ordering at the interface, solvent-ligand interpenetration, and ligand ordering relative to the particle surface. Only the smallest particles exhibited significant corrugation. All ligands permitted substantial solvent-ligand interpenetration, and ligand chain length has a significant influence on the orientational ordering of interfacial solvent. Solvent-ligand vibrational overlap, particularly in the low frequency range ($< 80 mathrm{cm}^{-1}$) was significantly altered by ligand rigidity, and had direct influence on the interfacial thermal conductance.","PeriodicalId":8439,"journal":{"name":"arXiv: Chemical Physics","volume":"55 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2016-01-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88800749","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 27
期刊
arXiv: Chemical Physics
全部 Acc. Chem. Res. ACS Applied Bio Materials ACS Appl. Electron. Mater. ACS Appl. Energy Mater. ACS Appl. Mater. Interfaces ACS Appl. Nano Mater. ACS Appl. Polym. Mater. ACS BIOMATER-SCI ENG ACS Catal. ACS Cent. Sci. ACS Chem. Biol. ACS Chemical Health & Safety ACS Chem. Neurosci. ACS Comb. Sci. ACS Earth Space Chem. ACS Energy Lett. ACS Infect. Dis. ACS Macro Lett. ACS Mater. Lett. ACS Med. Chem. Lett. ACS Nano ACS Omega ACS Photonics ACS Sens. ACS Sustainable Chem. Eng. ACS Synth. Biol. Anal. Chem. BIOCHEMISTRY-US Bioconjugate Chem. BIOMACROMOLECULES Chem. Res. Toxicol. Chem. Rev. Chem. Mater. CRYST GROWTH DES ENERG FUEL Environ. Sci. Technol. Environ. Sci. Technol. Lett. Eur. J. Inorg. Chem. IND ENG CHEM RES Inorg. Chem. J. Agric. Food. Chem. J. Chem. Eng. Data J. Chem. Educ. J. Chem. Inf. Model. J. Chem. Theory Comput. J. Med. Chem. J. Nat. Prod. J PROTEOME RES J. Am. Chem. Soc. LANGMUIR MACROMOLECULES Mol. Pharmaceutics Nano Lett. Org. Lett. ORG PROCESS RES DEV ORGANOMETALLICS J. Org. Chem. J. Phys. Chem. J. Phys. Chem. A J. Phys. Chem. B J. Phys. Chem. C J. Phys. Chem. Lett. Analyst Anal. Methods Biomater. Sci. Catal. Sci. Technol. Chem. Commun. Chem. Soc. Rev. CHEM EDUC RES PRACT CRYSTENGCOMM Dalton Trans. Energy Environ. Sci. ENVIRON SCI-NANO ENVIRON SCI-PROC IMP ENVIRON SCI-WAT RES Faraday Discuss. Food Funct. Green Chem. Inorg. Chem. Front. Integr. Biol. J. Anal. At. Spectrom. J. Mater. Chem. A J. Mater. Chem. B J. Mater. Chem. C Lab Chip Mater. Chem. Front. Mater. Horiz. MEDCHEMCOMM Metallomics Mol. Biosyst. Mol. Syst. Des. Eng. Nanoscale Nanoscale Horiz. Nat. Prod. Rep. New J. Chem. Org. Biomol. Chem. Org. Chem. Front. PHOTOCH PHOTOBIO SCI PCCP Polym. Chem.
×
引用
GB/T 7714-2015
复制
MLA
复制
APA
复制
导出至
BibTeX EndNote RefMan NoteFirst NoteExpress
×
0
微信
客服QQ
Book学术公众号 扫码关注我们
反馈
×
意见反馈
请填写您的意见或建议
请填写您的手机或邮箱
×
提示
您的信息不完整,为了账户安全,请先补充。
现在去补充
×
提示
您因"违规操作"
具体请查看互助需知
我知道了
×
提示
现在去查看 取消
×
提示
确定
Book学术官方微信
Book学术文献互助
Book学术文献互助群
群 号:481959085
Book学术
文献互助 智能选刊 最新文献 互助须知 联系我们:info@booksci.cn
Book学术提供免费学术资源搜索服务,方便国内外学者检索中英文文献。致力于提供最便捷和优质的服务体验。
Copyright © 2023 Book学术 All rights reserved.
ghs 京公网安备 11010802042870号 京ICP备2023020795号-1