In this paper, the internal mechanism of solid deuterium spatial distribution induced by infrared radiation is studied. The changes in spatial distribution and micro-structure of solid deuterium are also discussed as the results of wavelength and heating time of IR light. It is found that the micro-structure of solid deuterium which is irradiated by a special IR light is changed from polycrystal to monocrystal, the solid deuterium is redistributed and becomes more uniform and transparent. The best wavelength of IR light for heating solid deuterium is 3140 nm. When the output power of 3140 nm IR light is 100 upW, the redistribution time of solid deuterium is about 18 min.
Using a home-made cryotarget system and infrared spectroscopy system, we measure the infrared absorption spectra of liquid hydrogen at low temperaturs. It is found that the fundamental vibration frequency of hydrogen molecule is 4237.3 cm-1. As liquid hydrogen cools from 19.75 K down to 16.75 K, the infrared absorption is enhanced. The vibration frequency of hydrogen molecules is calculated on the basis of non-harmonic approximation in order to explain the experimental ones.
The effect of cooling rate on layering the deuterium ice inside inertial confinement fusion (ICF)spherical cryotarget is studied by backlit shadowgraphy. Experimentally, the temperature of ice is first determined by the calibration of temperature field around ICF cryotarget. The solidification process of deuterium in the cryotarget is in- situ characterized by backlit shadowgraphy. The power-spectrum density of the bright ring in shadowgraphy at different cooling rates is obtained. Experimental results demonstrate that the step-gradient slow cooling is favorable for forming uniform fuel ice in comparison with the rapid cooling. Furthermore, the validity of characterizing the ICF cryotarget layering by the backlit shadowgraphy is also verified.
The vibration/rotation modes and the corresponding infrared spectra of deuterium molecules with the D2d/D2h structures are calculated using the coupled cluster singles and doubles method with the cc-PVTZ basis sets within the framework of the density function theory. The infrared (IR) absorption spectrum of liquid deuterium is experimentally measured in a home-made cryogenic target system by a home-made low-temperature infrared spectroscope. The experimental results show that the strongest IR absorption peak of liquid deuterium is related to the Q1(0)+S0(0) mode, which is in good agreement with the theoretical calculation.
The vibration feature in a molecule solid is an important character of its structure. The different vibration frequencies of isolated nitrogen molecule (N2) and nitrogen molecule in the solid state are explored. Five solid-cluster models with the different numbers of nitrogen molecules (N46, N60, N76, N100, and N126) are constructed on the basis of -N2 crystal structures. The density functional theory is used to calculate the vibration frequencies of nitrogen molecules. The calculated infrared spectra and average vibration frequencies (AVFs) of the optimized structures for the five models are compared with each other. The results indicate that the AVF of nitrogen molecule in solid model is higher than that of isolated nitrogen molecule due to the collective effect. It is found that the AVF increases with increasing the number of molecules. The AVF of the inner molecules is always higher than that of surface molecules in the solid. On a whole, the vibration frequencies are ordered as vinner vsurface visolated for each case. The local coordination environment is believed to be mainly responsible for the differences in frequency among the isolated, surface and inner molecules. The bond length of molecule in solid is shorter than that in an isolated molecule, thus resulting in a stronger bond force and a higher vibration frequency. Similarly, due to a smaller number of molecules interacting with surface molecules, the bond force between molecules in the solid surface is weaker, thus resulting in a lower vibration frequency than in the inner region of solid.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.