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報告摘要
Lecture 1
TDDFT, from optical spectra to ultrafast non-equilibrium dynamics In this lecture, time-dependent density functional theory (TDDFT) will be presented as a versatile and affordable method to deal with the dynamics of electronic systems. Some remarks will be offered on the history and pre-history of the foundation of TDDFT which, ultimately, led to the formulation and proof of the Runge-Gross theorem. Most applications to date have focused on the response to weak probes, thus providing a decent and low-cost description of spectroscopic data. In recent years, real-time TDDFT simulations of strongly driven systems have become increasingly popular to predict the dynamical behavior far from thermal equilibrium. We shall visualize the laser-induced formation and breaking of chemical bonds in real time, and we shall highlight non-steady-state features of the electronic current through nano-scale junctions. With the goal of pushing magnetic storage processes towards ever faster time scales, an optically induced spin transfer (OISTR) from one magnetic sub-lattice to another will be presented. The OISTR effect was first predicted in 2016 by TDDFT calculations and two years later confirmed in several experiments, marking the birth of “atto-magnetism”.
Lecture 2
The exact factorization, a universal approach to non-adiabaticity Some of the most fascinating phenomena in chemistry and physics, such as the process of vision or laser-induced structural phase transitions in solids, involve the coupled motion of electrons and nuclei beyond the adiabatic approximation. To tackle such processes not captured by the dynamics on a single Born-Oppenheimer surface, we deduce an exact factorization of the full electron-nuclear wave function into a purely nuclear part and a many-electron wave function which parametrically depends on the nuclear configuration and which has the meaning of a conditional probability amplitude. The equations of motion of these two wave functions provide an ideal starting point to develop efficient algorithms for the study of non-adiabatic phenomena. Calculations of laser-induced isomerization processes, vibrational circular dichroism, the description of decoherence, as well as calculations of the molecular Berry phase without invoking the Born-Oppenheimer approximation, will demonstrate the power of this new approach. Finally, we shall address the question “which masses vibrate in a molecule”. While in the adiabatic approximation only the bare nuclear masses move on a single potential energy surface, it is intuitively clear that the electrons should move together with the nuclear degrees of freedom. Starting from the exact factorization, we include the electronic motion involved in molecular vibrations in a perturbative way via position-dependent nuclear masses. This method constitutes a general and rigorous framework for describing the mass acquired by the heavy degrees of freedom due to the presence of additional light particles in the system. Thus, it is applicable not only to electrons and nuclei (where the effect is tiny) but also in systems composed of light and heavy nuclei. We illustrate this idea with a model of proton transfer in a hydrogen bond O─H─O where nonadiabatic (vibrational) effects are known to be important.
報告人簡介
Eberhard K. U. Gross教授是含時密度泛函理論(TDDFT)的奠基人。他與Erich Runge一起證明了著名的Runge-Gross定理,為TDDFT奠定了數學基礎。此外,他是将線性響應TDDFT用于計算分子光譜的先驅,還将實時TDDFT應用于超快電子動力學的計算,在理論上首先預言了磁性材料中光誘導的自旋轉移現象,并很快被實驗證實。在材料計算方面,他進一步發展了用于激發态計算的系綜DFT理論,以及聲子驅動超導的第一性原理方法。近年來,他發展了針對原子核-電子體系的嚴格分解(exact factorization)方法,用于描述化學反應中的非絕熱動力學,特别是涉及電子退相幹以及分子幾何相位效應的化學過程。
報告人履曆
獲獎經曆