Phosgene is highly toxic, and it plays a role in the depletion of the ozone layer. The ground state geometric structure and spectral characteristic of phosgene in various external electric fields were calculated via t...Phosgene is highly toxic, and it plays a role in the depletion of the ozone layer. The ground state geometric structure and spectral characteristic of phosgene in various external electric fields were calculated via the density-functional theory (DFT) and time-dependent density-functional theory (TDDFT) with the B3LYP/6-31+G(d) basis set. With external electric field, the structure of phosgene changed significantly. With increasing electric field, the bond lengths of 1C-3Cl and 1C-4Cl increased;the total energy and energy gap initially increased and then decreased, whereas the dipole moment initially decreased and then increased. Most of the IR vibrational frequencies were redshifted. The wavelength of the singlet excited state increased, reflecting a red shift, and the oscillator strengths of most transitions belonged to forbidden transitions. These results are of great significance for studying the dissociation of phosgene in external electric field.展开更多
Several orders of magnitude of change in resistance are observed upon chemical doping and dedoping of the conducting polymer polyaniline.This large conductivity range can be utilized to make sensitive chemical sensors...Several orders of magnitude of change in resistance are observed upon chemical doping and dedoping of the conducting polymer polyaniline.This large conductivity range can be utilized to make sensitive chemical sensors.Polyaniline,in its nanofiber form,has even greater sensing capabilities due to the small fiber diameters,high surface area,and porous nanofiber network that enhances gas diffusion into the fibers.Polyaniline nanofibers have been synthesized using a rapid mixing method and dispersed in water allowing them to be easily modified with water soluble agents,making new composite materials.Polyaniline nanofiber composite materials can be used to enhance detection of analytes that unmodified polyaniline would not otherwise be able to detect.The detection mechanism involves the reaction of an additive with the analyte to generate a strong acid that is easily detected by polyaniline,resulting in orders of magnitude changes in resistance.The reaction of the additive alone with the analyte produces no electrical response,however.In this paper,an array of amine-polyaniline nanofiber composite materials is investigated for the detection of phosgene gas.The influence of environmental conditions such as humidity and temperature are examined and a detection mechanism is presented.展开更多
基金National Natural Science Foundation of China(Grant Number:21763027)Innovation Team for Monitoring of Emerging Contaminants and Biomarkers(Grant Number:2021D14017)+2 种基金Xinjiang Regional Collaborative Innovation Project(Grant Number:2019E0223)Scientific Research Program of Colleges and Universities in Xinjiang(Grant Number:XJEDU2020Y029)“13th Five-Year”Plan for Key Discipline Physics Bidding Project of Xinjiang Normal University(Grant Number:17SDKD0602).
文摘Phosgene is highly toxic, and it plays a role in the depletion of the ozone layer. The ground state geometric structure and spectral characteristic of phosgene in various external electric fields were calculated via the density-functional theory (DFT) and time-dependent density-functional theory (TDDFT) with the B3LYP/6-31+G(d) basis set. With external electric field, the structure of phosgene changed significantly. With increasing electric field, the bond lengths of 1C-3Cl and 1C-4Cl increased;the total energy and energy gap initially increased and then decreased, whereas the dipole moment initially decreased and then increased. Most of the IR vibrational frequencies were redshifted. The wavelength of the singlet excited state increased, reflecting a red shift, and the oscillator strengths of most transitions belonged to forbidden transitions. These results are of great significance for studying the dissociation of phosgene in external electric field.
基金the Aerospace Corporation’s Independent Research and Development Program(BHW)the National Science Foundation Grant DMR 0507294(RBK).
文摘Several orders of magnitude of change in resistance are observed upon chemical doping and dedoping of the conducting polymer polyaniline.This large conductivity range can be utilized to make sensitive chemical sensors.Polyaniline,in its nanofiber form,has even greater sensing capabilities due to the small fiber diameters,high surface area,and porous nanofiber network that enhances gas diffusion into the fibers.Polyaniline nanofibers have been synthesized using a rapid mixing method and dispersed in water allowing them to be easily modified with water soluble agents,making new composite materials.Polyaniline nanofiber composite materials can be used to enhance detection of analytes that unmodified polyaniline would not otherwise be able to detect.The detection mechanism involves the reaction of an additive with the analyte to generate a strong acid that is easily detected by polyaniline,resulting in orders of magnitude changes in resistance.The reaction of the additive alone with the analyte produces no electrical response,however.In this paper,an array of amine-polyaniline nanofiber composite materials is investigated for the detection of phosgene gas.The influence of environmental conditions such as humidity and temperature are examined and a detection mechanism is presented.
