An Efficient Method for Determining Matrix Elements of the Dipole Moment Operator and Corrections to the Energy of a Polyatomic Molecule Using the Perturbation Theory within the Polynomials of Quantum Numbers Formalism

2021 ◽  
Author(s):  
M. Yu. Yur’ev ◽  
V. M. Vakhromov ◽  
A. O. Voloshchenko ◽  
L. B. Klink
Keyword(s):  
Perturbation Theory ◽  
Dipole Moment ◽  
Efficient Method ◽  
Polyatomic Molecule ◽  
Matrix Elements ◽  
Dipole Moment Operator ◽  
Quantum Numbers ◽  
Moment Operator

Broadband EM radiation amplification by means of a monochromatically driven two-level system

2017 ◽  
Vol 31 (04) ◽  
pp. 1750027 ◽  
Author(s):  
Andrey V. Soldatov
Keyword(s):  
Dipole Moment ◽  
Quantum System ◽  
High Frequency ◽  
Laser Field ◽  
Diagonal Matrix ◽  
Matrix Elements ◽  
Level System ◽  
Dipole Moment Operator ◽  
Moment Operator ◽  
Radiation Amplification

It is shown that a two-level quantum system possessing dipole moment operator with permanent non-equal diagonal matrix elements and driven by external semiclassical monochromatic high-frequency electromagnetic (EM) (laser) field can amplify EM radiation waves of much lower frequency.

Microwave Transient Phenomena of Symmetric Top Molecules. An Extended Bloch Type Description

1978 ◽  
Vol 33 (12) ◽  
pp. 1493-1497 ◽  
Author(s):  
H. Mäder ◽  
H. Bomsdorf
Keyword(s):  
Dipole Moment ◽  
Electric Dipole ◽  
Population Difference ◽  
Level System ◽  
Transient Phenomena ◽  
Dipole Moment Operator ◽  
Emission Signal ◽  
Moment Operator ◽  
Macroscopic Polarization ◽  
Symmetric Top Molecules

Abstract The Bloch equations for the macroscopic polarization components Pr and Pi and the population difference ⊿N of a two-level system are derived with inclusion of diagonal elements of the electric dipole moment operator. The influence of such elements on the solutions is discussed. The effect of Stark-switching technique on the observed transient emission signal is considered.

The torsional dependence of the dipole moment operator in methyl silane

1986 ◽  
Vol 119 (2) ◽  
pp. 313-330 ◽  
Author(s):  
H Jagannath ◽  
I Ozier ◽  
N Moazzen-Ahmadi
Keyword(s):  
Dipole Moment ◽  
Dipole Moment Operator ◽  
Moment Operator

ChemInform Abstract: The Torsional Dependence of the Dipole Moment Operator in Methyl Silane.

ChemInform ◽  
1987 ◽  
Vol 18 (5) ◽  
Author(s):  
H. JAGANNATH ◽  
I. OZIER ◽  
N. MOAZZEN-AHMADI
Keyword(s):  
Dipole Moment ◽  
Dipole Moment Operator ◽  
Moment Operator

scholarly journals FIRST-PRINCIPLES SIMULATION OF THE CERIUM TRIFLUORIDE INFRARED SPECTRUM BEYOND THE BORN–OPPENHEIMER APPROXIMATION

2018 ◽  
Vol 61 (3) ◽  
pp. 31
Author(s):  
Oleg A. Vasilyev ◽  
Viktor G. Solomonik
Keyword(s):  
Dipole Moment ◽  
First Principles ◽  
Orbit Coupling ◽  
Spin Orbit Coupling ◽  
Spin Orbit ◽  
Dipole Moment Operator ◽  
Cerium Trifluoride ◽  
Jahn Teller ◽  
Moment Operator ◽  
Oppenheimer Approximation

The group-theoretical analysis was carried out to derive a spin-vibronic model Hamiltonian and a diabatic dipole moment operator for a cerium trihalide molecule, CeX3. The model comprises seven lowest-lying 4f1 electronic states coupled by six vibrational modes, (A2'' + E' + E'' + A1' + A2') × (a1' + a2'' + e' + e'), with an accounting for spin-orbit coupling. Multimode potential energy surfaces have been calculated for the CeF3 molecule at the multi-reference singles and doubles configuration interaction level of theory corrected for quadruple excitations, MRCISD+Q, and dipole moment surfaces at the MRCISD level. A hybrid approach employing a quasi-diabatization technique was utilized to determine the relevant model parameters up to forth order in power series of the Q1(a1'), Q3(e'), Q4(e') normal coordinates, and eighth order of the Q2(a2'') out-of-plane bending normal coordinate. Spin-orbit coupling was taken into account through zero-order, with the respective constants obtained from matrix elements of the Breit–Pauli operator in the basis of states generated at the MRCISD level. The spin-vibronic Hamiltonian and dipole moment operator obtained in this way has been utilized in the variational calculations to simulate the infrared absorption spectrum of CeF3. The resulting spectrum features a complex structure owing to an intricate interplay of the vibronic (Jahn–Teller and pseudo-Jahn–Teller) and spin-orbit coupling effects, and hence cannot be explained within the conventional Born–Oppenheimer (BO) approximation. The strongest absorption appearing in the simulated spectrum at about 500 cm–1, mostly associated with the Q3(e') stretching mode, is split into two bands by about 3 cm–1. This finding is in full agreement with the CeF3 matrix isolation infrared spectroscopy data. On the whole, the results of the calculations clearly indicate the vibronic rather than vibrational origin of the spectral bands, including the bands in the low-frequency region of the spectrum, and thus show the fallacy of the generally accepted assignment of the bands observed in the experiment to the fundamental vibrational transitions of the molecule made on the assumption of the admissibility of describing this within the Born–Oppenheimer approximation. The new assignment of the experimental IR spectrum of CeF3 is proposed.Forcitation:Vasilyev O.A., Solomonik V.G. First-principles simulation of the cerium trifluoride infrared spectrum beyond the Born–Oppenheimer approximation. Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol. 2018. V. 61. N 3. P. 31-44

Laser frequency down-conversion by means of a monochromatically driven two-level system

2016 ◽  
Vol 30 (27) ◽  
pp. 1650331 ◽  
Author(s):  
Andrey V. Soldatov
Keyword(s):  
High Frequency ◽  
Laser Field ◽  
Laser Frequency ◽  
Practical Implementation ◽  
Matrix Elements ◽  
Level System ◽  
Dipole Moment Operator ◽  
Wide Range ◽  
Moment Operator ◽  
Down Conversion

Conditions are found under which a simple two-level quantum system possessing dipole moment operator with permanent non-equal diagonal matrix elements and driven by external semiclassical monochromatic high-frequency EM (laser) field can radiate continuously at much lower frequency. Possible ways to experimental observation and practical implementation of the predicted effect for a wide range of applications are discussed.

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