scholarly journals Evaluating excited state atomic polarizabilities of chromophores

2018 ◽  
Vol 20 (13) ◽  
pp. 8554-8563 ◽  
Author(s):  
Esther Heid ◽  
Patricia A. Hunt ◽  
Christian Schröder
Keyword(s):  
Quantum Mechanics ◽  
Excited State ◽  
Coumarin 153

Ground and excited state atomic polarizabilities of the chromophoresN-methyl-6-oxyquinolinium betaine and coumarin 153 have been evaluatedviaquantum mechanics.

Visualization and Manipulation of Molecular Motion in Solid State through Photo-Induced Clusteroluminescence

2019 ◽  
Author(s):  
Haoke Zhang ◽  
Lili Du ◽  
Lin Wang ◽  
Junkai Liu ◽  
Qing Wan ◽  
...  
Keyword(s):  
Quantum Mechanics ◽  
Excited State ◽  
Solid State ◽  
Light Source ◽  
Molecular Motion ◽  
Molecular Machine ◽  
Conjugated Molecules ◽  
Time Resolved ◽  
Packing Structure ◽  
New Strategy

<p>Building molecular machine has long been a dream of scientists as it is expected to revolutionize many aspects of technology and medicine. Implementing the solid-state molecular motion is the prerequisite for a practical molecular machine. However, few works on solid-state molecular motion have been reported and it is almost impossible to “see” the motion even if it happens. Here the light-driven molecular motion in solid state is discovered in two non-conjugated molecules <i>s</i>-DPE and <i>s</i>-DPE-TM, resulting in the formation of excited-state though-space complex (ESTSC). Meanwhile, the newly formed ESTSC generates an abnormal visible emission which is termed as clusteroluminescence. Notably, the original packing structure can recover from ESTSC when the light source is removed. These processes have been confirmed by time-resolved spectroscopy and quantum mechanics calculation. This work provides a new strategy to manipulate and “see” solid-state molecular motion and gains new insights into the mechanistic picture of clusteroluminescence.<br></p>

scholarly journals Quantum mechanics of particles trapped in a Lamé circle or Lamé sphere shaped potential well

2021 ◽  
Vol 67 (2 Mar-Apr) ◽  
pp. 206
Author(s):  
T. Isojärvi
Keyword(s):  
Quantum Mechanics ◽  
Excited State ◽  
Undergraduate Students ◽  
Ground State ◽  
State Energy ◽  
Potential Well ◽  
Step Potential ◽  
Time Stepping ◽  
Data Points ◽  
Well Depth

Ground state and 1st excited state energies and wave functions were calculated for systems of one or two electrons in a 2D and 3D potential well having a shape intermediate between a circle and a square or a sphere and a cube. One way to define such a potential well is with a step potential and a bounding surface of form |x| q +|y| q +|z| q = |r| q , which converts from a sphere to a cube when q increases from 2 to infinity. This kind of geometrical object is called a Lame surface. The calculations were done either with implicit finite difference time stepping in ´ the direction of negative imaginary time axis or with quantum diffusion Monte Carlo. The results demonstrate how the volume and depth of the potential well affect the E0 more than the shape parameter q does. Functions of two and three parameters were found to be sufficient for fitting an empirical graph to the ground state energy data points as a function of well depth V0 or exponent q. The ground state and first excited state energy of one particle in a potential well of this type appeared to be very closely approximated with an exponential function depending on q, when the well depth and area or volume was kept constant while changing the value of q. The model is potentially useful for describing quantum dots that deviate from simple geometric shapes, or for demonstrating methods of computational quantum mechanics to undergraduate students.

Visualization and Manipulation of Molecular Motion in Solid State through Photo-Induced Clusteroluminescence

2019 ◽  
Author(s):  
Haoke Zhang ◽  
Lili Du ◽  
Lin Wang ◽  
Junkai Liu ◽  
Qing Wan ◽  
...  
Keyword(s):  
Quantum Mechanics ◽  
Excited State ◽  
Solid State ◽  
Light Source ◽  
Molecular Motion ◽  
Molecular Machine ◽  
Conjugated Molecules ◽  
Time Resolved ◽  
Packing Structure ◽  
New Strategy

<p>Building molecular machine has long been a dream of scientists as it is expected to revolutionize many aspects of technology and medicine. Implementing the solid-state molecular motion is the prerequisite for a practical molecular machine. However, few works on solid-state molecular motion have been reported and it is almost impossible to “see” the motion even if it happens. Here the light-driven molecular motion in solid state is discovered in two non-conjugated molecules <i>s</i>-DPE and <i>s</i>-DPE-TM, resulting in the formation of excited-state though-space complex (ESTSC). Meanwhile, the newly formed ESTSC generates an abnormal visible emission which is termed as clusteroluminescence. Notably, the original packing structure can recover from ESTSC when the light source is removed. These processes have been confirmed by time-resolved spectroscopy and quantum mechanics calculation. This work provides a new strategy to manipulate and “see” solid-state molecular motion and gains new insights into the mechanistic picture of clusteroluminescence.<br></p>

Ultrafast vibrational evolution of excited-state coumarin 153 using fs/ps CARS as a transient Raman probe

2006 ◽  
pp. 66-69 ◽  
Author(s):  
Benjamin D. Prince ◽  
Abhijit Chakraborty ◽  
Beth M. Prince ◽  
Tse-Ming Hsin ◽  
Hans U. Stauffer
Keyword(s):  
Excited State ◽  
Coumarin 153 ◽  
Raman Probe

Computational Photobiology and Beyond

2010 ◽  
Vol 63 (3) ◽  
pp. 413 ◽  
Author(s):  
Igor Schapiro ◽  
Mikhail N. Ryazantsev ◽  
Wan Jian Ding ◽  
Mark M. Huntress ◽  
Federico Melaccio ◽  
...  
Keyword(s):  
Quantum Mechanics ◽  
Excited State ◽  
Ab Initio ◽  
Molecular Mechanics ◽  
Chemical Treatment ◽  
Quantum Chemical ◽  
Organic Molecules ◽  
Molecular Devices ◽  
Computational Studies ◽  
Computational Investigation

In this paper we review the results of a group of computational studies of the spectroscopy and photochemistry of light-responsive proteins. We focus on the use of quantum mechanics/molecular mechanics protocols based on a multiconfigurational quantum chemical treatment. More specifically, we discuss the use, limitations, and application of the ab initio CASPT2//CASSCF protocol that, presently, constitutes the method of choice for the investigation of excited state organic molecules, most notably, biological chromophores and fluorophores. At the end of this Review we will also see how the computational investigation of the visual photoreceptor rhodopsin is providing the basis for the design of light-driven artificial molecular devices.

Excited-state hydrogen bond strengthening of coumarin 153 in ethanol solvent: a TDDFT study

2016 ◽  
Vol 29 (6) ◽  
pp. 305-311 ◽  
Author(s):  
Jinmei Xu ◽  
Junsheng Chen ◽  
Shunle Dong ◽  
Aiping Fu ◽  
Hongliang Li ◽  
...  
Keyword(s):  
Hydrogen Bond ◽  
Excited State ◽  
Coumarin 153 ◽  
Hydrogen Bond Strengthening

Asymptotic Functional Form Preservation Method with Supersymmetric Quantum Mechanics for Anharmonic Oscillators

2016 ◽  
Vol 69 (9) ◽  
pp. 950 ◽  
Author(s):  
Chia-Chun Chou ◽  
Ching-Teh Li
Keyword(s):  
Quantum Mechanics ◽  
Excited State ◽  
Series Expansion ◽  
Functional Form ◽  
Full Range ◽  
Supersymmetric Quantum Mechanics ◽  
Anharmonic Oscillators ◽  
Approximate Analytical Expression ◽  
Preservation Method ◽  
Functional Forms

The asymptotic functional form preservation method is developed in the framework of supersymmetric quantum mechanics to obtain the energies and wave functions of anharmonic oscillators. For each of the ground states in the hierarchy of supersymmetric partner Hamiltonians, we derive a series expansion of the superpotential for . Employing a transformation containing an unphysical parameter, we convert the series expansion of the superpotential into a new series expansion applicable to all the range of x. The unphysical parameter is determined by the principle of minimal sensitivity. Requiring the preservation of the correct asymptotic functional form of the full-range series expansion as x tends to infinity, we obtain the ground and excited state energies. The truncated full-range series expansion for the superpotential provides an approximate analytical expression for the wave function. In addition, several ansatz functional forms are also proposed for the superpotential to obtain the ground and excited state energies with high accuracy. Excellent computational results for the anharmonic oscillator demonstrate that the method proposed here is suitable for solving similar quantum mechanical problems.

GENERALIZED BÄCKLUND–DARBOUX TRANSFORMATIONS IN ONE-DIMENSIONAL QUANTUM MECHANICS

2008 ◽  
Vol 05 (04) ◽  
pp. 605-640 ◽  
Author(s):  
JOSÉ F. CARIÑENA ◽  
ARTURO RAMOS
Keyword(s):  
Quantum Mechanics ◽  
Excited State ◽  
Differential Expression ◽  
Transformation Group ◽  
Darboux Transformations ◽  
Singular Case ◽  
One Dimensional ◽  
First Order ◽  
The Difference ◽  
Usual Problem

We consider an action of the group of curves in GL(2,ℝ) on the set of linear systems and therefore on the set of Schrödinger equations in full similarity with the action of the group of curves in SL(2,ℝ) on the set of Riccati equations considered in previous articles. We also consider the transformations defined by a first-order differential expression which carry solutions of a Schrödinger equation into solutions of another one. We find then two non-trivial situations: transformations which can be described by the previous transformation group, generalizing previous work by us, and transformations which are singular. We show that both situations appear, e.g., in the usual problem of partner Hamiltonians in quantum mechanics. We show that the difference Bäcklund algorithm, both in the finite and confluent versions, can be understood in terms of the above mentioned transformation group, the case of two exactly equal factorization energies being an instance of the singular case. We apply the generalized theorem relating three eigenfunctions of three different Hamiltonians to the generation of new potentials with a known (excited state) eigenfunction, starting from potentials of Coulomb, Morse and Rosen–Morse type. The potentials found are new and non-trivial.

Comparison of the mean field and Bohmian semi-classical approximations to the Rabi model

2021 ◽  
pp. 2150270
Author(s):  
Dirk-André Deckert ◽  
Leopold Kellers ◽  
Travis Norsen ◽  
Ward struyve
Keyword(s):  
Quantum Mechanics ◽  
Excited State ◽  
Measurement Problem ◽  
Mean Field ◽  
Bohmian Mechanics ◽  
Back Reaction ◽  
Standard Quantum ◽  
Level Atom ◽  
Classical Approximation ◽  
Rabi Model

Bohmian mechanics is an alternative to standard quantum mechanics that does not suffer from the measurement problem. While it agrees with standard quantum mechanics concerning its experimental predictions, it offers novel types of approximations not suggested by the latter. Of particular interest are semi-classical approximations, where part of the system is treated classically. Bohmian semi-classical approximations have been explored before for systems without electromagnetic interactions. Here, the Rabi model is considered as a simple model involving light-matter interaction. This model describes a single mode electromagnetic field interacting with a two-level atom. As is well-known, the quantum treatment and the semi-classical treatment (where the field is treated classically rather than quantum mechanically) give qualitatively different results. We analyze the Rabi model using a different semi-classical approximation based on Bohmian mechanics. In this approximation, the back-reaction from the two-level atom onto the classical field is mediated by the Bohmian configuration of the two-level atom. We find that the Bohmian semi-classical approximation gives results comparable to the usual mean field one for the transition between ground and first excited state. Both semi-classical approximations tend to reproduce the collapse of the population inversion, but fail to reproduce the revival, which is characteristic of the full quantum description. Also an example of a higher excited state is presented where the Bohmian approximation does not perform so well.

Sign in / Sign up

Export Citation Format

Share Document