### Abstract

We present a multiscale modeling and computational scheme for optical-mechanical responses of nanostructures. The multi-physical nature of the problem is a result of the interaction between the electromagnetic (EM) field, the molecular motion, and the electronic excitation. To balance accuracy and complexity, we adopt the semi-classical approach that the EM field is described classically by the Maxwell equations, and the charged particles follow the Schrödinger equations quantum mechanically. To overcome the numerical challenge of solving the high dimensional multi-component many-body Schrödinger equations, we further simplify the model with the Ehrenfest molecular dynamics to determine the motion of the nuclei, and use the Time-Dependent Current Density Functional Theory (TD-CDFT) to calculate the excitation of the electrons. This leads to a system of coupled equations that computes the electromagnetic field, the nuclear positions, and the electronic current and charge densities simultaneously. In the regime of linear responses, the resonant frequencies initiating the out-of-equilibrium optical-mechanical responses can be formulated as an eigenvalue problem. A self-consistent multiscale method is designed to deal with the well separated space scales. The isomerization of azobenzene is presented as a numerical example.

Original language | English (US) |
---|---|

Pages (from-to) | 558-572 |

Number of pages | 15 |

Journal | Journal of Computational Physics |

Volume | 316 |

DOIs | |

State | Published - Jul 1 2016 |

### Profile

### Keywords

- Ehrenfest dynamics
- Eigenvalue problem
- Maxwell equations
- Multiscale modeling and computation
- Nanostructures
- Optical responses
- Resonant condition
- Time-dependent current density functional theory

### ASJC Scopus subject areas

- Computer Science Applications
- Physics and Astronomy (miscellaneous)

### Cite this

*Journal of Computational Physics*,

*316*, 558-572. DOI: 10.1016/j.jcp.2016.04.033

**Multiscale modeling and computation of optically manipulated nano devices.** / Bao, Gang; Liu, Di; Luo, Songting.

Research output: Contribution to journal › Article

*Journal of Computational Physics*, vol 316, pp. 558-572. DOI: 10.1016/j.jcp.2016.04.033

}

TY - JOUR

T1 - Multiscale modeling and computation of optically manipulated nano devices

AU - Bao,Gang

AU - Liu,Di

AU - Luo,Songting

PY - 2016/7/1

Y1 - 2016/7/1

N2 - We present a multiscale modeling and computational scheme for optical-mechanical responses of nanostructures. The multi-physical nature of the problem is a result of the interaction between the electromagnetic (EM) field, the molecular motion, and the electronic excitation. To balance accuracy and complexity, we adopt the semi-classical approach that the EM field is described classically by the Maxwell equations, and the charged particles follow the Schrödinger equations quantum mechanically. To overcome the numerical challenge of solving the high dimensional multi-component many-body Schrödinger equations, we further simplify the model with the Ehrenfest molecular dynamics to determine the motion of the nuclei, and use the Time-Dependent Current Density Functional Theory (TD-CDFT) to calculate the excitation of the electrons. This leads to a system of coupled equations that computes the electromagnetic field, the nuclear positions, and the electronic current and charge densities simultaneously. In the regime of linear responses, the resonant frequencies initiating the out-of-equilibrium optical-mechanical responses can be formulated as an eigenvalue problem. A self-consistent multiscale method is designed to deal with the well separated space scales. The isomerization of azobenzene is presented as a numerical example.

AB - We present a multiscale modeling and computational scheme for optical-mechanical responses of nanostructures. The multi-physical nature of the problem is a result of the interaction between the electromagnetic (EM) field, the molecular motion, and the electronic excitation. To balance accuracy and complexity, we adopt the semi-classical approach that the EM field is described classically by the Maxwell equations, and the charged particles follow the Schrödinger equations quantum mechanically. To overcome the numerical challenge of solving the high dimensional multi-component many-body Schrödinger equations, we further simplify the model with the Ehrenfest molecular dynamics to determine the motion of the nuclei, and use the Time-Dependent Current Density Functional Theory (TD-CDFT) to calculate the excitation of the electrons. This leads to a system of coupled equations that computes the electromagnetic field, the nuclear positions, and the electronic current and charge densities simultaneously. In the regime of linear responses, the resonant frequencies initiating the out-of-equilibrium optical-mechanical responses can be formulated as an eigenvalue problem. A self-consistent multiscale method is designed to deal with the well separated space scales. The isomerization of azobenzene is presented as a numerical example.

KW - Ehrenfest dynamics

KW - Eigenvalue problem

KW - Maxwell equations

KW - Multiscale modeling and computation

KW - Nanostructures

KW - Optical responses

KW - Resonant condition

KW - Time-dependent current density functional theory

UR - http://www.scopus.com/inward/record.url?scp=84964403965&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84964403965&partnerID=8YFLogxK

U2 - 10.1016/j.jcp.2016.04.033

DO - 10.1016/j.jcp.2016.04.033

M3 - Article

VL - 316

SP - 558

EP - 572

JO - Journal of Computational Physics

T2 - Journal of Computational Physics

JF - Journal of Computational Physics

SN - 0021-9991

ER -