基于扩展随机相位近似方法的亚迪亚巴特连接方法的多参考相关振荡器强度
Daria Drwal1, Katarzyna Pernal1, Ewa Pastorczak1
1Institute of Physics, Lodz University of Technology, ul. Wolczanska 217/221, 93-005 Lodz, Poland.
Journal of chemical theory and computation
|April 26, 2024
概括
精确的振荡器强度可以通过使用附带电流连接 (AC) 方法与扩展随机相近似 (ERPA) 和多引用波函数来实现. 这些交流方法为电子刺激计算提供了具有竞争力的准确性,并降低了电子刺激计算的计算成本.
科学领域:
- 计算化学计算化学
- 量子化学 是一个量子化学.
- 理论光谱学 理论光谱学
背景情况:
- 精确计算电子刺激特性,如振荡器强度,对于理解分子行为和光谱至关重要.
- 像CASPT2和NEVPT2这样的传统方法虽然准确,但在计算上可能很苛刻,特别是在较大的系统中.
- 阿迪亚巴特连接 (AC) 方法为计算电子属性提供了一个有希望的替代方案,其计算成本可能更低.
研究的目的:
- 为了证明电连接 (AC) 方法与扩展随机相近似 (ERPA) 和多引用 (CAS) 波函数相结合的准确性,用于计算振荡器强度.
- 引入和评估乱校正的ERPA过渡密度矩阵和AC相关能量方法 (AC0,AC0D) 用于激发能量和振荡器强度计算.
- 评估与已建立的多配置扰动理论相比,新的交流方法的计算扩展和效率.
主要方法:
- 运用了附带连接 (AC) 理论与扩展随机相近似 (ERPA) 和完全活性空间 (CAS) 波函数相结合.
- 为振荡器强度计算开发并应用了经扰动校正的ERPA过渡密度矩阵.
- 采用AC0和AC0D方法来计算激发能量,并测试三重激发的AC0D.
主要成果:
- 使用AC-ERPA-CAS方法获得了精确的振荡器强度.
- AC0和AC0D方法提供了与CASPT2相比具有竞争力的激发能量,但计算精力显著降低.
- 与CASPT2和NEVPT2.2相比,AC0和AC0D的活跃轨道数量具有有利的缩放.
- 开发了一种新的,无成本的方法来计算相关过渡双极时刻.
- AC0D校正提高了单元和三元激发能量的准确性,特别是对于低状态.
结论:
- 阿迪亚巴特连接方法,特别是AC0和AC0D,为计算电子激发属性提供了计算效率高和准确的途径.
- 开发的乱校正ERPA过渡密度矩阵和AC方法为传统的高级计算方法提供了可行的替代方案.
- 这些发现为更容易获得和更准确的分子系统理论光谱学铺平了道路.
相关概念视频
Maxwell's Thermodynamic Relations
2.7K
Maxwell's thermodynamic relations are very useful in solving problems in thermodynamics. Each of Maxwell's relations relates a partial differential between quantities that can be hard to measure experimentally to a partial differential between quantities that can be easily measured. These relations are a set of equations derivable from the symmetry of the second derivatives and the thermodynamic potentials.
All thermodynamic potentials are exact differentials. Therefore, their second-order...
All thermodynamic potentials are exact differentials. Therefore, their second-order...
2.7K
RLC Circuit as a Damped Oscillator
966
An RLC circuit combines a resistor, inductor, and capacitor, connected in a series or parallel combination.
Consider a series RLC circuit. Here, the presence of resistance in the circuit leads to energy loss due to joule heating in the resistance. Therefore, the total electromagnetic energy in the circuit is no longer constant and decreases with time. Since the magnitude of charge, current, and potential difference continuously decreases, their oscillations are said to be damped. This is...
Consider a series RLC circuit. Here, the presence of resistance in the circuit leads to energy loss due to joule heating in the resistance. Therefore, the total electromagnetic energy in the circuit is no longer constant and decreases with time. Since the magnitude of charge, current, and potential difference continuously decreases, their oscillations are said to be damped. This is...
966
Oscillations In An LC Circuit
2.3K
An idealized LC circuit of zero resistance can oscillate without any source of emf by shifting the energy stored in the circuit between the electric and magnetic fields. In such an LC circuit, if the capacitor contains a charge q before the switch is closed, then all the energy of the circuit is initially stored in the electric field of the capacitor. This energy is given by
2.3K
Adiabatic Processes for an Ideal Gas
3.1K
When an ideal gas is compressed adiabatically, that is, without adding heat, work is done on it, and its temperature increases. In an adiabatic expansion, the gas does work, and its temperature drops. Adiabatic compressions actually occur in the cylinders of a car, where the compressions of the gas-air mixture take place so quickly that there is no time for the mixture to exchange heat with its environment. Nevertheless, because work is done on the mixture during the compression, its...
3.1K
Propagation of Uncertainty from Random Error
681
An experiment often consists of more than a single step. In this case, measurements at each step give rise to uncertainty. Because the measurements occur in successive steps, the uncertainty in one step necessarily contributes to that in the subsequent step. As we perform statistical analysis on these types of experiments, we must learn to account for the propagation of uncertainty from one step to the next. The propagation of uncertainty depends on the type of arithmetic operation performed on...
681
Phasor Relationships for Circuit Elements
534
Phasor representation is a powerful tool used to transform the voltage-current relationship for resistors, inductors, and capacitors from the time domain to the frequency domain. This transformation simplifies the analysis of alternating current (AC) circuits.
In the time domain, Ohm's law provides a fundamental relation between the current flowing through a resistor and the voltage across it:
In the time domain, Ohm's law provides a fundamental relation between the current flowing through a resistor and the voltage across it:
534


