量子浴增强的随机不平衡原子模拟用于分子导热传导的原子模拟.
Renai Chen1,2, Mohammadhasan Dinpajooh3, Abraham Nitzan1,4
1Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA.
The Journal of chemical physics
|October 6, 2023
概括
本研究介绍了一种模拟分子热传导的准经典方法,将量子效应纳入所有温度的准确性. 这种新方法通过准确地建模量子环境,改进了经典的分子动力学 (MD).
科学领域:
- 计算物理学的计算物理.
- 材料科学是一种材料科学.
- 纳米技术纳米技术
背景情况:
- 经典分子动力学 (MD) 模拟热传导,但在低温下缺乏量子效应.
- 量子兰道尔类型模型忽略了关键因素,如无调性和非线性响应.
研究的目的:
- 开发一个包括量子效应在内的分子热传导的原子模拟方法.
- 为了创建一个适合广泛温度范围的模型,从低到高的温度.
主要方法:
- 将量子斯-爱因斯坦统计纳入"有效温度"中,使用修改后的朗格温方程.
- 模拟了使用莫尔斯电位的无声模型,并将它们与波相互作用进行了比较.
- 检查了量子增强浴的1D聚合物链中的热传导.
主要成果:
- 准经典方法在低温下显示了与经典MD的显著偏差,在高温下趋同.
- 该方法准确地模拟了基质布局和分子性质,如非和性和高频模式.
- 对聚合物链的热传导的链长度依赖性进行了分析.
结论:
- 开发的准经典有效温度MD方法准确地捕捉了分子导热中的量子效应.
- 这种方法是通用的,适用于各种分子系统和温度范围.
- 这些发现为了解纳米尺度的热传输提供了更强大的工具.
相关概念视频
02:45The Quantum-Mechanical Model of an Atom
42.4K
Shortly after de Broglie published his ideas that the electron in a hydrogen atom could be better thought of as being a circular standing wave instead of a particle moving in quantized circular orbits, Erwin Schrödinger extended de Broglie’s work by deriving what is now known as the Schrödinger equation. When Schrödinger applied his equation to hydrogen-like atoms, he was able to reproduce Bohr’s expression for the energy and, thus, the Rydberg formula governing hydrogen spectra.
42.4K
02:46Quantifying Heat
54.6K
Thermal Energy Microscopically, thermal energy is the kinetic energy associated with the random motion of atoms and molecules. Temperature is a quantitative measure of “hot” or “cold”, which depends on the amount of thermal energy. When the atoms and molecules in an object are moving or vibrating quickly, they have a higher average kinetic energy (KE) (or higher thermal energy), and the object is perceived as “hot”, or it is described as being at a...
54.6K
01:14Mechanisms of Heat Transfer I
4.3K
Just as interesting as the effects of heat transfer on a system are the methods by which the heat transfer occur. Whenever there is a temperature difference, heat transfer occurs. It may occur rapidly, such as through a cooking pan, or slowly, such as through the walls of a picnic ice box. So many processes involve heat transfer that it is hard to imagine a situation where no heat transfer occurs. Yet, every heat transfer takes place by only three methods: conduction, convection, and radiation.
4.3K
01:20Mechanisms of Heat Transfer II
3.3K
In convection, thermal energy is carried by the large-scale flow of matter. Ocean currents and large-scale atmospheric circulation, which result from the buoyancy of warm air and water, transfer hot air from the tropics toward the poles and cold air from the poles toward the tropics. The Earth’s rotation interacts with those flows, causing the observed eastward flow of air in the temperate zones. Convection dominates heat transfer by air, and the amount of available space for the airflow...
3.3K
01:14Mechanisms of Heat Transfer
343
Heat transfer between the human body and its environment occurs through four main mechanisms: conduction, convection, radiation, and evaporation.
Conduction, accounting for approximately 3% of body heat loss at rest, is the process of exchanging heat between molecules of two materials in direct contact. This can result in both heat loss and gain. For instance, when the body is submerged in water, which conducts heat 20 times more effectively than air, it can either lose or gain significant...
Conduction, accounting for approximately 3% of body heat loss at rest, is the process of exchanging heat between molecules of two materials in direct contact. This can result in both heat loss and gain. For instance, when the body is submerged in water, which conducts heat 20 times more effectively than air, it can either lose or gain significant...
343
01:16Specific Heat
62.2K
The specific heat capacity of a substance refers to the energy required to increase the temperature of one gram of that substance by one degree Celcius. Specific heat capacity is often represented in calories (cal), grams (g), and degrees Celsius (oC), but can also be expressed in joules (J), kilograms (kg), and Kelvin (K), among other units.
For example, increasing the temperature of one gram of water by 1°C requires one calorie of heat energy and can be written as 1 cal/g-°C, or...
For example, increasing the temperature of one gram of water by 1°C requires one calorie of heat energy and can be written as 1 cal/g-°C, or...
62.2K