The luminescence of Nd3+-doped in NaBi(WO4)2 single crystal was investigated from 10 K to room temperature.The excitation source was a pulsed dye laser in resonance into the(4G5/2+2G(1)7/2) levels of Nd3+ ions.Several...The luminescence of Nd3+-doped in NaBi(WO4)2 single crystal was investigated from 10 K to room temperature.The excitation source was a pulsed dye laser in resonance into the(4G5/2+2G(1)7/2) levels of Nd3+ ions.Several blue emission bands in the up-conversion luminescence spectra corresponded to transitions from 2P1/2 to 4I9/2.Some violet bands corresponding to transitions of 4D3/2→(4I9/2,4I11/2,4I13/2) were also observed.For comparison,the luminescence spectra and decay curves excited by the pulsed 355 nm laser were measured.In order to investigate up-conversion mechanisms,the decay behavior and the dependence of the up-conversion luminescence on laser powers were investigated.The temporal decay behavior of the up-conversion luminescence indicated that the two-photon excited state absorption of the Nd3+ ions was the dominant mechanism in this crystal.展开更多
A series of YNbO_(4):Bi^(3+) and YNbO_(4):Bi^(3+)/Er^(3+) phosphors were prepared by a conventional high temperature solid-state reaction method.The results of XRD and Rietveld refinement confirm that monoclinic phase...A series of YNbO_(4):Bi^(3+) and YNbO_(4):Bi^(3+)/Er^(3+) phosphors were prepared by a conventional high temperature solid-state reaction method.The results of XRD and Rietveld refinement confirm that monoclinic phase YNbO_(4)samples are achieved.The down-/up-conversion luminescence of Er^(3+) ions was investigated under the excitation of ultraviolet light(327 nm)and near infrared light(980 nm).Under 327 nm excitation,broad visible emission band from Bi^(3+) ions and characteristic green emission peaks from Er^(3+) ions are simultaneously observed,while only strong green emissions from Er^(3+) ions are detected upon excitation of 980 nm.Remarkable emission enhancement is observed in down-/up-conversion luminescence processes by introducing Bi^(3+) ions into Er^(3+)-doped YNbO_(4)phosphors.Pumped current versus up-conversion emission intensity study shows that two-photon processes are responsible for both the green and the red up-conversion emissions of Er^(3+)ion.Through the study of the temperature sensing property of Er^(3+) ion,it is affirmed that the temperature sensitivity is sensitive to the doping concentration of Bi^(3+) ions.By comparing the experimental values of the radiative transition rate ratio of the two green emission levels of Er^(3+) ions and the theoretical values calculated by Judd-Ofelt(J-O)theory,it is concluded that the temperature sensing property of Er^(3+) ions is greatly affected by the energy level splitting.展开更多
Er^(3+)and Yb^(3+)co-doped CaBi_(2)Ta_(2)O_(9)(CBT)-based bismuth layered-structure oxides were synthesized by a simple solid-state reaction method.Their up-conversion(UC)luminescence,dielectric and ferroelectric prop...Er^(3+)and Yb^(3+)co-doped CaBi_(2)Ta_(2)O_(9)(CBT)-based bismuth layered-structure oxides were synthesized by a simple solid-state reaction method.Their up-conversion(UC)luminescence,dielectric and ferroelectric properties were investigated.Two strong green emission bands centered at 526 and 547nm and a weak red emission band centered at 658nm were obtained under a 980nm laser excitation at room temperature.These emission bands originated from the radiative relaxation of Er^(3+)from 2H_(11)=2,4S_(3)=2,and 4F_(9/2) levels to the ground state 4I_(15)=2,respectively.At the meantime,the fluorescence intensity ratio(FIR)variation of two green UC emissions at 526 and 547nm has been studied as a function of temperature in the range of 153–603K.The maximum sensor sensitivity obtained was 39×10^(-4)K^(-1) at 590K,which indicated that Er^(3+)=Yb^(3+)co-doped CBT ceramic is a promising candidate for applications in optical high temperature sensor.展开更多
A series of Yb^(3+)/Er^(3+) or Er^(3+) doped SrIn_2O_4 were synthesized by a high temperature solid state method.The up-conversion luminescence property and the phase formation of SrIn_2O_4:Er^(3+) and SrIn_2O_4:Yb^(3...A series of Yb^(3+)/Er^(3+) or Er^(3+) doped SrIn_2O_4 were synthesized by a high temperature solid state method.The up-conversion luminescence property and the phase formation of SrIn_2O_4:Er^(3+) and SrIn_2O_4:Yb^(3+),Er^(3+) were investigated by X-ray diffraction(XRD) and spectral methods.The XRD pattern shows that incorporating different amounts of Yb^(3+)and Er^(3+) have no influence on the phase formation of SrIn_2O_4.The up-conversion luminescence spectrum of SrIn_2O_4:Er^(3+) presented a weak luminescence due to ground state absorption of Er^(3+).However,Yb^(3+)/Er^(3+) codoped SrIn_2O_4 depicted the green(525 and 551 run) and red(662 nm) up-conversion luminescence which were assigned to the energy transfer from the Yb^(3+) transition ~2F_(7/2)-~2F_(5/2) to the Er^(3+) transitions ~2H_(11/2)-~4I_(15/2) and ~4F_(9/2-~4I_(15/2),respectively.The possible up-conversion luminescence mechanism of SrIn_2O_4:Yb^(3+),Er^(3+) was analyzed.All results could be helpful to the development of up-conversion luminescence materials.展开更多
The Er3+doped double perovskite Ba_(2)CaWO_(6) crystal is a promising ratiometric thermometer based on the fluorescence intensity ratio(FIR) of transitions from ^(2)H_(11/2) and ^(4)S_(3/2) to the lowered ^(4)I_(15/2)...The Er3+doped double perovskite Ba_(2)CaWO_(6) crystal is a promising ratiometric thermometer based on the fluorescence intensity ratio(FIR) of transitions from ^(2)H_(11/2) and ^(4)S_(3/2) to the lowered ^(4)I_(15/2) level.However,the Ca^(2+) vacancy defect caused by the charge difference between rare-earth ions and the substituted alkaline-earth ions gives rise to the non-radiative probability and limits the thermal sensitivity.Here,the up-conversion luminescence and thermometric performance of Er^(3+),Yb^(3+) dopedBa_(2)CaWO_(6) are tuned by tri-doping with alkaline ions.The Ca^(2+) vacancy defect can be eliminated by the introduction of Na^(+),which occupies the Ca^(2+) site when it is doped into Ba_(2)CaWO_(6) with Er^(3+) and Yb^(3+).On the contrary,the doping of Cs^(+) into Ba_(2)CaWO_(6) with Er^(3+) and Yb^(3+) enhances the defect concentration because it occupies the site of Ba^(2+).Thus,the tri-doping of Na^(+) reduces the non-radiative probability and enhances the quantum efficiency of Er^(3+),leading to the improvement of the thermometric sensitivity of Ba_(2)CaWO_(6).As a result,we get an excellent thermometric Ba_(2)CaWO_(6):8%Yb^(3+),3.5%Er^(3+),6%Na^(+) powder with a luminescence lifetime of 515 μs and maximum thermal sensitivity(S_(r)) of 1.45%/K,which is more than three times higher than that of the BCWO:Er^(3+) powder.展开更多
Herein,we reported novel Y_(4)GeO_(8):Er^(3+),Yb^(3+)phosphors elaborated via conventional solid-state reaction.and we further explored their properties as optical thermometer by using fluorescence intensity ratio(FIR...Herein,we reported novel Y_(4)GeO_(8):Er^(3+),Yb^(3+)phosphors elaborated via conventional solid-state reaction.and we further explored their properties as optical thermometer by using fluorescence intensity ratio(FIR)method complemented by detailed analysis on crystal structure,up-conversion luminescence and energy transfer from Yb^(3+)to Er^(3+).Upon 980 nm laser excitation,Y_(4)GeO_(8):Er^(3+),Yb^(3+)phosphors present525,547 and 659 nm emission bands assigned to the characteristic transitions of Er^(3+).Furthermore,Y_(4)GeO_(8):Er^(3+),Yb^(3+)samples show outstanding temperature sensing performances.To be specific,the minimal temperature resolution is 0.03 K(303 K),and the relative sensitivity of FIR can be up to 1.152%/K(303 K).Hence,Y_(4)GeO_(8):Er^(3+),Yb^(3+)phosphors can be possible candidates for thermometry devices.展开更多
A microemulsion-mediated hydrothermal method for synthesis of YVO4:RE(RE=Yb 3+/Er 3+,Yb 3+/Tm 3+)nanoparticles by hydrothermal treatment of quaternary microemulsion medium consisting of Na3VO4/NaOH and RE(NO3)3 aqueou...A microemulsion-mediated hydrothermal method for synthesis of YVO4:RE(RE=Yb 3+/Er 3+,Yb 3+/Tm 3+)nanoparticles by hydrothermal treatment of quaternary microemulsion medium consisting of Na3VO4/NaOH and RE(NO3)3 aqueous solution, surfactant cetyltrimethylammonium bromide(CTAB),cosurfactant n-hexanol and oil phase n-heptane was report.The confinement of microemulsion droplets acting as microreactors during the reaction process allows the formation of small size YVO4:RE nanoparticles with relatively narrow size distribution and less aggregation.The structure,size and shape of YVO4:RE nanoparticles were investigated by means of X-ray diffractometry(XRD)and transmission electron microscopy(TEM).Compared with the conventional solid annealing diffusion method,the microemulsion-mediated hydrothermal method shows superiority in obtaining YVO4:RE nanoparticles with controllable size,narrow size distribution and less aggregation.The microemulsion-mediated hydrothermal method may be potentially applicable for synthesis of other rare earth doped up-converting luminescence nanomaterials.展开更多
Ho doping 0.825K_(0.5)Na_(0.5)NbO_(3)-0.175Sr(Yb_(0.5)Nb_(0.5))_(O3)(KNN-SYbN-x%Ho)transparent ceramics were prepared by solid-state sintering method.The structure,ferroelectric,energy storage,and optical properties o...Ho doping 0.825K_(0.5)Na_(0.5)NbO_(3)-0.175Sr(Yb_(0.5)Nb_(0.5))_(O3)(KNN-SYbN-x%Ho)transparent ceramics were prepared by solid-state sintering method.The structure,ferroelectric,energy storage,and optical properties of KNN-SYbN-x%Ho were explored.With the addition of Ho,under the excitation of a 980 nm laser,the ceramics exhibit up-conversion luminescence properties with wavelengths of 550 nm and 670 nm,however,the ceramics change from pseudo-cubic phase to triphase-orthorhombic phase and the light transmittance decreases.The addition of Ho significantly enhances the ferroelectric properties and the energy storage performance of KNN-SYbN-x%Ho ceramics.When x=0.15,the residual polarization P_(r)=9.11μC/cm^(2),while x=0.20,the maximum energy storage density W_(rec) reaches 0.26 J/cm^(3),and the energy storage efficiencyηreaches 87.1%.展开更多
Multifunctional ceramics of 0.825K_(0.5)Na_(0.5)NbO_(3)-0.175Sr(Yb_(0.5)Nb_(0.5))O_(3)-x%Er with ferroelectric,transparent and luminescent properties were obtained by doping Er.The effects of Er-doping on the structur...Multifunctional ceramics of 0.825K_(0.5)Na_(0.5)NbO_(3)-0.175Sr(Yb_(0.5)Nb_(0.5))O_(3)-x%Er with ferroelectric,transparent and luminescent properties were obtained by doping Er.The effects of Er-doping on the structure,luminescence and electrical properties of the ceramics were studied.After Er doping,the ceramics have luminescent properties and the luminescence intensity reaches the maximum when x=0.75.The ceramics still have good light transmission,but the transmittance decreases with the increase of Er-doping content due to the change of phase structure from pseudo-cubic phase to three-phase orthogonality.The energy storage properties is also greatly improved,and the W_(rec) and the η of the ceramics reach the maximum value of 0.31 J/cm^(3) and 94.6% when x=0.25,respectively.At the same time,the maximum electro-induced strain value is 0.031%.展开更多
Long afterglow organic-inorganic hybrid materials have attracted much attention in recent years and are widely used in information security, biological imaging and many other fields. Since up-conversion long-persisten...Long afterglow organic-inorganic hybrid materials have attracted much attention in recent years and are widely used in information security, biological imaging and many other fields. Since up-conversion long-persistence materials are promising for bio-optical imaging due to their high penetration depth and elimination of autofluorescence background, it is highly desirable to combine down-conversion and up-conversion pathways to obtain smart materials with excitation-dependent tunable room-temperature phosphorescence properties. In this work, a metal-organic framework(Zn-DCPS-BIMB), consisting of divalent zinc ions, o-bis(imidazol-1-ylmethyl)benzene and 4,4-dicarboxydiphenylsulfone, is designed to stabilize triplet excitons, coordinate the emission of different ligands, and endow materials with tunable emission color and up-conversion properties via heavy atoms effects promoting single-triplet orbital coupling and intersystem crossing.展开更多
基金supported by the Korea Science and Engineering Foundation (KOSEF) Grant funded by the Korean Government (MEST) (2009-0078682)
文摘The luminescence of Nd3+-doped in NaBi(WO4)2 single crystal was investigated from 10 K to room temperature.The excitation source was a pulsed dye laser in resonance into the(4G5/2+2G(1)7/2) levels of Nd3+ ions.Several blue emission bands in the up-conversion luminescence spectra corresponded to transitions from 2P1/2 to 4I9/2.Some violet bands corresponding to transitions of 4D3/2→(4I9/2,4I11/2,4I13/2) were also observed.For comparison,the luminescence spectra and decay curves excited by the pulsed 355 nm laser were measured.In order to investigate up-conversion mechanisms,the decay behavior and the dependence of the up-conversion luminescence on laser powers were investigated.The temporal decay behavior of the up-conversion luminescence indicated that the two-photon excited state absorption of the Nd3+ ions was the dominant mechanism in this crystal.
基金Project supported by the National Natural Science Foundation of China(11774042,11704056)Fundamental Research Funds for the Central Universities(3132020177,3132019338)。
文摘A series of YNbO_(4):Bi^(3+) and YNbO_(4):Bi^(3+)/Er^(3+) phosphors were prepared by a conventional high temperature solid-state reaction method.The results of XRD and Rietveld refinement confirm that monoclinic phase YNbO_(4)samples are achieved.The down-/up-conversion luminescence of Er^(3+) ions was investigated under the excitation of ultraviolet light(327 nm)and near infrared light(980 nm).Under 327 nm excitation,broad visible emission band from Bi^(3+) ions and characteristic green emission peaks from Er^(3+) ions are simultaneously observed,while only strong green emissions from Er^(3+) ions are detected upon excitation of 980 nm.Remarkable emission enhancement is observed in down-/up-conversion luminescence processes by introducing Bi^(3+) ions into Er^(3+)-doped YNbO_(4)phosphors.Pumped current versus up-conversion emission intensity study shows that two-photon processes are responsible for both the green and the red up-conversion emissions of Er^(3+)ion.Through the study of the temperature sensing property of Er^(3+) ion,it is affirmed that the temperature sensitivity is sensitive to the doping concentration of Bi^(3+) ions.By comparing the experimental values of the radiative transition rate ratio of the two green emission levels of Er^(3+) ions and the theoretical values calculated by Judd-Ofelt(J-O)theory,it is concluded that the temperature sensing property of Er^(3+) ions is greatly affected by the energy level splitting.
基金This work was supported by the Natural Science Foundation of China(No.51072136).
文摘Er^(3+)and Yb^(3+)co-doped CaBi_(2)Ta_(2)O_(9)(CBT)-based bismuth layered-structure oxides were synthesized by a simple solid-state reaction method.Their up-conversion(UC)luminescence,dielectric and ferroelectric properties were investigated.Two strong green emission bands centered at 526 and 547nm and a weak red emission band centered at 658nm were obtained under a 980nm laser excitation at room temperature.These emission bands originated from the radiative relaxation of Er^(3+)from 2H_(11)=2,4S_(3)=2,and 4F_(9/2) levels to the ground state 4I_(15)=2,respectively.At the meantime,the fluorescence intensity ratio(FIR)variation of two green UC emissions at 526 and 547nm has been studied as a function of temperature in the range of 153–603K.The maximum sensor sensitivity obtained was 39×10^(-4)K^(-1) at 590K,which indicated that Er^(3+)=Yb^(3+)co-doped CBT ceramic is a promising candidate for applications in optical high temperature sensor.
文摘A series of Yb^(3+)/Er^(3+) or Er^(3+) doped SrIn_2O_4 were synthesized by a high temperature solid state method.The up-conversion luminescence property and the phase formation of SrIn_2O_4:Er^(3+) and SrIn_2O_4:Yb^(3+),Er^(3+) were investigated by X-ray diffraction(XRD) and spectral methods.The XRD pattern shows that incorporating different amounts of Yb^(3+)and Er^(3+) have no influence on the phase formation of SrIn_2O_4.The up-conversion luminescence spectrum of SrIn_2O_4:Er^(3+) presented a weak luminescence due to ground state absorption of Er^(3+).However,Yb^(3+)/Er^(3+) codoped SrIn_2O_4 depicted the green(525 and 551 run) and red(662 nm) up-conversion luminescence which were assigned to the energy transfer from the Yb^(3+) transition ~2F_(7/2)-~2F_(5/2) to the Er^(3+) transitions ~2H_(11/2)-~4I_(15/2) and ~4F_(9/2-~4I_(15/2),respectively.The possible up-conversion luminescence mechanism of SrIn_2O_4:Yb^(3+),Er^(3+) was analyzed.All results could be helpful to the development of up-conversion luminescence materials.
基金Project supported by the National Natural Science Foundation of China (51972061,22109025,22171045,52072076)。
文摘The Er3+doped double perovskite Ba_(2)CaWO_(6) crystal is a promising ratiometric thermometer based on the fluorescence intensity ratio(FIR) of transitions from ^(2)H_(11/2) and ^(4)S_(3/2) to the lowered ^(4)I_(15/2) level.However,the Ca^(2+) vacancy defect caused by the charge difference between rare-earth ions and the substituted alkaline-earth ions gives rise to the non-radiative probability and limits the thermal sensitivity.Here,the up-conversion luminescence and thermometric performance of Er^(3+),Yb^(3+) dopedBa_(2)CaWO_(6) are tuned by tri-doping with alkaline ions.The Ca^(2+) vacancy defect can be eliminated by the introduction of Na^(+),which occupies the Ca^(2+) site when it is doped into Ba_(2)CaWO_(6) with Er^(3+) and Yb^(3+).On the contrary,the doping of Cs^(+) into Ba_(2)CaWO_(6) with Er^(3+) and Yb^(3+) enhances the defect concentration because it occupies the site of Ba^(2+).Thus,the tri-doping of Na^(+) reduces the non-radiative probability and enhances the quantum efficiency of Er^(3+),leading to the improvement of the thermometric sensitivity of Ba_(2)CaWO_(6).As a result,we get an excellent thermometric Ba_(2)CaWO_(6):8%Yb^(3+),3.5%Er^(3+),6%Na^(+) powder with a luminescence lifetime of 515 μs and maximum thermal sensitivity(S_(r)) of 1.45%/K,which is more than three times higher than that of the BCWO:Er^(3+) powder.
基金Project supported by National Natural Science Foundation of China(11974315)Guangdong Science and Technology Innovation Strategy Foundation of China(20190310)。
文摘Herein,we reported novel Y_(4)GeO_(8):Er^(3+),Yb^(3+)phosphors elaborated via conventional solid-state reaction.and we further explored their properties as optical thermometer by using fluorescence intensity ratio(FIR)method complemented by detailed analysis on crystal structure,up-conversion luminescence and energy transfer from Yb^(3+)to Er^(3+).Upon 980 nm laser excitation,Y_(4)GeO_(8):Er^(3+),Yb^(3+)phosphors present525,547 and 659 nm emission bands assigned to the characteristic transitions of Er^(3+).Furthermore,Y_(4)GeO_(8):Er^(3+),Yb^(3+)samples show outstanding temperature sensing performances.To be specific,the minimal temperature resolution is 0.03 K(303 K),and the relative sensitivity of FIR can be up to 1.152%/K(303 K).Hence,Y_(4)GeO_(8):Er^(3+),Yb^(3+)phosphors can be possible candidates for thermometry devices.
基金Projects(20601012,20601016,20961005)supported by the National Natural Science Foundation of ChinaProject(209024)supported by the Ministry of Education of ChinaProjects(206077,206043,10013-121008)supported by Inner Mongolia University,China
文摘A microemulsion-mediated hydrothermal method for synthesis of YVO4:RE(RE=Yb 3+/Er 3+,Yb 3+/Tm 3+)nanoparticles by hydrothermal treatment of quaternary microemulsion medium consisting of Na3VO4/NaOH and RE(NO3)3 aqueous solution, surfactant cetyltrimethylammonium bromide(CTAB),cosurfactant n-hexanol and oil phase n-heptane was report.The confinement of microemulsion droplets acting as microreactors during the reaction process allows the formation of small size YVO4:RE nanoparticles with relatively narrow size distribution and less aggregation.The structure,size and shape of YVO4:RE nanoparticles were investigated by means of X-ray diffractometry(XRD)and transmission electron microscopy(TEM).Compared with the conventional solid annealing diffusion method,the microemulsion-mediated hydrothermal method shows superiority in obtaining YVO4:RE nanoparticles with controllable size,narrow size distribution and less aggregation.The microemulsion-mediated hydrothermal method may be potentially applicable for synthesis of other rare earth doped up-converting luminescence nanomaterials.
基金Funded by the National Nature Science Foundation of China(No.61965007)the Guangxi Nature Science Foundation,China(No.2018GXNSFDA281042)the Guangxi Key Laboratory of Information Materials(Guilin University of Electronic Technology),China(No.201007-Z)。
文摘Ho doping 0.825K_(0.5)Na_(0.5)NbO_(3)-0.175Sr(Yb_(0.5)Nb_(0.5))_(O3)(KNN-SYbN-x%Ho)transparent ceramics were prepared by solid-state sintering method.The structure,ferroelectric,energy storage,and optical properties of KNN-SYbN-x%Ho were explored.With the addition of Ho,under the excitation of a 980 nm laser,the ceramics exhibit up-conversion luminescence properties with wavelengths of 550 nm and 670 nm,however,the ceramics change from pseudo-cubic phase to triphase-orthorhombic phase and the light transmittance decreases.The addition of Ho significantly enhances the ferroelectric properties and the energy storage performance of KNN-SYbN-x%Ho ceramics.When x=0.15,the residual polarization P_(r)=9.11μC/cm^(2),while x=0.20,the maximum energy storage density W_(rec) reaches 0.26 J/cm^(3),and the energy storage efficiencyηreaches 87.1%.
基金Supported by the National Natural Science Foundation of China (No.61965007)Guangxi Natual Science Foundation (No.2018GXNSFDA281042)Guangxi Key Laboratory of Information Materials (No.201007-Z)。
文摘Multifunctional ceramics of 0.825K_(0.5)Na_(0.5)NbO_(3)-0.175Sr(Yb_(0.5)Nb_(0.5))O_(3)-x%Er with ferroelectric,transparent and luminescent properties were obtained by doping Er.The effects of Er-doping on the structure,luminescence and electrical properties of the ceramics were studied.After Er doping,the ceramics have luminescent properties and the luminescence intensity reaches the maximum when x=0.75.The ceramics still have good light transmission,but the transmittance decreases with the increase of Er-doping content due to the change of phase structure from pseudo-cubic phase to three-phase orthogonality.The energy storage properties is also greatly improved,and the W_(rec) and the η of the ceramics reach the maximum value of 0.31 J/cm^(3) and 94.6% when x=0.25,respectively.At the same time,the maximum electro-induced strain value is 0.031%.
基金supported by the Beijing Municipal Natural Science Foundation (No. JQ20003)the National Natural Science Foundation of China (Nos. 21771021, 21822501 and 22061130206)+3 种基金the Newton Advanced Fellowship award (No. NAFR1201285)the Fok Ying-Tong Education Foundation (No. 171008)the Measurements Fund of Beijing Normal Universitythe State Key Laboratory of Heavy Oil Processing。
文摘Long afterglow organic-inorganic hybrid materials have attracted much attention in recent years and are widely used in information security, biological imaging and many other fields. Since up-conversion long-persistence materials are promising for bio-optical imaging due to their high penetration depth and elimination of autofluorescence background, it is highly desirable to combine down-conversion and up-conversion pathways to obtain smart materials with excitation-dependent tunable room-temperature phosphorescence properties. In this work, a metal-organic framework(Zn-DCPS-BIMB), consisting of divalent zinc ions, o-bis(imidazol-1-ylmethyl)benzene and 4,4-dicarboxydiphenylsulfone, is designed to stabilize triplet excitons, coordinate the emission of different ligands, and endow materials with tunable emission color and up-conversion properties via heavy atoms effects promoting single-triplet orbital coupling and intersystem crossing.
