Conservation of Angular Momentum in Direct Nonadiabatic Dynamics

Shu, Yinan; Zhang, Linyao; Varga, Zoltán; Parker, Kelsey; Kanchanakungwankul, Siriluk; Sun, Shaozeng; Truhlar, Donald G.

doi:10.1021/acs.jpclett.9b03749

Cited by 26 publications

(54 citation statements)

References 32 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This comes as no surprise, since the CP method per se emphasizes 13 C close to 1 H. Moreover, the dynamics of the CP method also depends on the orientation of heteronuclear dipolar tensors, Hartmann-Hahn match conditions (mismatch, relaxation effects), molecular motion and MAS rate. 52 For these reasons, the solid state 13 C-CP/MAS NMR method gives information regarding all the bulk material and an indicative estimation of the total degree of substitution of the substituents throughout the cellulose fibre. The peaks in the 13 C CP/MAS solid state NMR-spectrum were assigned according to the literature.…”

Section: Resultsmentioning

confidence: 99%

Chemically modified cellulose nanofibril as an additive for two‐component polyurethane coatings

Virtanen¹,

Jämsä²,

Talja³

et al. 2018

J of Applied Polymer Sci

View full text Add to dashboard Cite

show abstract

Section: Resultsmentioning

confidence: 99%

Chemically modified cellulose nanofibril as an additive for two‐component polyurethane coatings

Virtanen¹,

Jämsä²,

Talja³

et al. 2018

J of Applied Polymer Sci

View full text Add to dashboard Cite

show abstract

“…Two common methods are isotropic velocity rescaling, and rescaling solely along the non-adiabatic coupling vector (NACV) [35]. While rescaling along the NACV is believed to be more justified theoretically from semiclassical arguments [37][38][39], both approaches have been recently shown to violate the principle of conservation of angular momentum [40]. In addition, NACV momentum rescaling means only kinetic energy along the NACV is available, and this can result in poorer internal consistency.…”

Section: (C) Trajectory Surface Hoppingmentioning

confidence: 99%

Mixed-quantum-classical or fully-quantized dynamics? A unified code to compare methods

Coonjobeeharry

Spinlove

Sanz-Sanz

et al. 2022

Phil. Trans. R. Soc. A.

View full text Add to dashboard Cite

Three methods for non-adiabatic dynamics are compared to highlight their capabilities. Multi-configurational time-dependent Hartree is a full grid-based solution to the time-dependent Schrödinger equation, variational multi-configurational Gaussian (vMCG) uses a less flexible but unrestricted Gaussian wavepacket basis, and trajectory surface hopping (TSH) replaces the nuclear wavepacket with a swarm of classical trajectories. Calculations with all methods using a model Hamiltonian were performed. The vMCG and TSH were also then run in a direct dynamics mode, with the potential energy surfaces calculated on-the-fly using quantum chemistry calculations. All dynamics calculations used the Q uantics package, with the TSH calculations using a new interface to a surface hopping code. A novel approach to calculate adiabatic populations from grid-based quantum dynamics using a time-dependent discrete variable representation is presented, allowing a proper comparison of methods. This article is part of the theme issue ‘Chemistry without the Born–Oppenheimer approximation’.

show abstract

“…As before, 75 it is necessary to project out the rotational and translational components of the effective NAC in order to conserve the total angular momentum and the position of the center of mass. This yields 75…”

Section: Theorymentioning

confidence: 99%

“…where 1 and Q are the identity matrix and a projection operator. 75 The operation in eq 20 removes unphysical translational and rotational components of . Therefore the nuclear EOM of κSE becomes:…”

Section: Theorymentioning

confidence: 99%

Nonadiabatic Dynamics Algorithms with Only Potential Energies and Gradients: Curvature-Driven Coherent Switching with Decay of Mixing and Curvature-Driven Trajectory Surface Hopping

Shu

Zhang

Sun

et al. 2021

Preprint

Self Cite

View full text Add to dashboard Cite

Direct dynamics by mixed quantum–classical nonadiabatic methods is an important tool for understanding processes involving multiple electronic states. Very often, the computational bottleneck of such direct simulation comes from electronic structure theory. For example, at every time step of a trajectory, nonadiabatic dynamics requires potential energy surfaces, their gradients, and the matrix elements coupling the surfaces. The need for the couplings can be alleviated by employing the time derivatives of the wave functions, which can be evaluated from overlaps of electronic wave functions at successive timesteps. However, evaluation of overlap integrals is still expensive for large systems. In addition, for electronic structure methods for which the wave functions or the coupling matrix elements are not available, nonadiabatic dynamics algorithms become inapplicable. In this work, building on recent work by Baeck and An, we propose new nonadiabatic dynamics algorithms that only require adiabatic potential energies and their gradients. The new methods are named curvature- driven coherent switching with decay of mixing (κCSDM) and curvature-driven trajectory surface hopping (κTSH). We show how powerful these new methods are in terms of computer time and good agreement with methods employing nonadiabatic coupling vectors computed in conventional ways. The lowering of the computational cost will allow longer nonadiabatic trajectories and greater ensemble averaging to be affordable, and the ability to calculate the dynamics without electronic structure coupling matrix elements extends the dynamics capability to new classes of electronic structure methods.

show abstract

Conservation of Angular Momentum in Direct Nonadiabatic Dynamics

Cited by 26 publications

References 32 publications

Chemically modified cellulose nanofibril as an additive for two‐component polyurethane coatings

Chemically modified cellulose nanofibril as an additive for two‐component polyurethane coatings

Mixed-quantum-classical or fully-quantized dynamics? A unified code to compare methods

Nonadiabatic Dynamics Algorithms with Only Potential Energies and Gradients: Curvature-Driven Coherent Switching with Decay of Mixing and Curvature-Driven Trajectory Surface Hopping

Contact Info

Product

Resources

About