Pushing the limits in accurate vibrational structure calculations: anharmonic frequencies of lithium fluoride clusters (LiF)n, n = 2–10

2014 ◽  
Vol 16 (31) ◽  
pp. 16426 ◽  
Author(s):  
Dominik Oschetzki ◽  
Guntram Rauhut
Keyword(s):  
Lithium Fluoride ◽  
Vibrational Structure ◽  
Anharmonic Frequencies ◽  
Structure Calculations ◽  
Vibrational Structure Calculations

A weight averaged approach for predicting amide vibrational bands of a sphingomyelin bilayer

2015 ◽  
Vol 17 (43) ◽  
pp. 29113-29123 ◽  
Author(s):  
Kiyoshi Yagi ◽  
Pai-Chi Li ◽  
Koichiro Shirota ◽  
Toshihide Kobayashi ◽  
Yuji Sugita
Keyword(s):  
Molecular Dynamics ◽  
Vibrational Structure ◽  
New Method ◽  
Vibrational Bands ◽  
Structure Calculations ◽  
Vibrational Structure Calculations

A new method is proposed, which combines molecular dynamics and vibrational structure calculations, to calculate the spectra of a sphingomyelin bilayer.

scholarly journals Hardware efficient quantum algorithms for vibrational structure calculations

2020 ◽  
Vol 11 (26) ◽  
pp. 6842-6855
Author(s):  
Pauline J. Ollitrault ◽  
Alberto Baiardi ◽  
Markus Reiher ◽  
Ivano Tavernelli
Keyword(s):  
Excited State ◽  
Quantum Algorithms ◽  
Vibrational Structure ◽  
Quantum Devices ◽  
Near Term ◽  
Structure Calculations ◽  
Vibrational Structure Calculations

We introduce a framework for the calculation of ground and excited state energies of bosonic systems suitable for near-term quantum devices and apply it to molecular vibrational anharmonic Hamiltonians.

Direct measurement of electron-diffraction-pattern intensities using an energy loss spectrometer

1989 ◽  
Vol 47 ◽  
pp. 668-669
Author(s):  
A. G. Jackson ◽  
M. Rowe
Keyword(s):  
Thermal Effects ◽  
Dynamic Range ◽  
Scattering Amplitude ◽  
Dynamical Theory ◽  
Site Symmetry ◽  
Proof Of Concept ◽  
Parallel Acquisition ◽  
Kinematic Approximation ◽  
Speed Up ◽  
Structure Calculations

Diffraction intensities from intermetallic compounds are, in the kinematic approximation, proportional to the scattering amplitude from the element doing the scattering. More detailed calculations have shown that site symmetry and occupation by various atom species also affects the intensity in a diffracted beam. [1] Hence, by measuring the intensities of beams, or their ratios, the occupancy can be estimated. Measurement of the intensity values also allows structure calculations to be made to determine the spatial distribution of the potentials doing the scattering. Thermal effects are also present as a background contribution. Inelastic effects such as loss or absorption/excitation complicate the intensity behavior, and dynamical theory is required to estimate the intensity value.The dynamic range of currents in diffracted beams can be 104or 105:1. Hence, detection of such information requires a means for collecting the intensity over a signal-to-noise range beyond that obtainable with a single film plate, which has a S/N of about 103:1. Although such a collection system is not available currently, a simple system consisting of instrumentation on an existing STEM can be used as a proof of concept which has a S/N of about 255:1, limited by the 8 bit pixel attributes used in the electronics. Use of 24 bit pixel attributes would easily allowthe desired noise range to be attained in the processing instrumentation. The S/N of the scintillator used by the photoelectron sensor is about 106 to 1, well beyond the S/N goal. The trade-off that must be made is the time for acquiring the signal, since the pattern can be obtained in seconds using film plates, compared to 10 to 20 minutes for a pattern to be acquired using the digital scan. Parallel acquisition would, of course, speed up this process immensely.

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