Pub Date : 2015-12-28DOI: 10.26713/JAMCNP.V2I3.336
D. Ciampini, O. Morsch, E. Arimondo
Ultracold atomic gases excited to strongly interacting Rydberg states are a promising system for quantum simulations of many-body systems. The dipole blockade of Rydberg excitations is a hallmark of the strong interactions between atoms in these high-lying quantum states. We have measured the Rydberg excitation for rubidium ultracold atoms in magneto-optical traps and for Bose-Einstein condensates loaded into quasi one-dimensional traps. One of the consequences of the dipole blockade is the suppression of fluctuations in the counting statistics of Rydberg excitations. We have obtained experimental results on the dynamics and the counting statistics of Rydberg excitations of ultra-cold Rubidium atoms both on and off resonance, which exhibit sub- and super-Poissonian counting statistics, respectively. We have found strongly bimodal counting distributions in the offresonant regime.
{"title":"Ultracold Rubidium Atoms Excited to Rydberg Levels","authors":"D. Ciampini, O. Morsch, E. Arimondo","doi":"10.26713/JAMCNP.V2I3.336","DOIUrl":"https://doi.org/10.26713/JAMCNP.V2I3.336","url":null,"abstract":"Ultracold atomic gases excited to strongly interacting Rydberg states are a promising system for quantum simulations of many-body systems. The dipole blockade of Rydberg excitations is a hallmark of the strong interactions between atoms in these high-lying quantum states. We have measured the Rydberg excitation for rubidium ultracold atoms in magneto-optical traps and for Bose-Einstein condensates loaded into quasi one-dimensional traps. One of the consequences of the dipole blockade is the suppression of fluctuations in the counting statistics of Rydberg excitations. We have obtained experimental results on the dynamics and the counting statistics of Rydberg excitations of ultra-cold Rubidium atoms both on and off resonance, which exhibit sub- and super-Poissonian counting statistics, respectively. We have found strongly bimodal counting distributions in the offresonant regime.","PeriodicalId":239838,"journal":{"name":"Journal of Atomic, Molecular, Condensate and Nano Physics","volume":"32 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-12-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133531610","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2015-12-04DOI: 10.26713/JAMCNP.V2I2.330
S. Upadhyay, K. Sreenivas
Nanostructured powder of MgFe(_2)O(_4) was prepared by sol gel auto combustion method using two different precursors. It is an ultimate combination of slow and sustained gel formation and subsequent combustion. In this work, our aim is to synthesize nanoparticles of MgFe(_2)O(_4) using different precursors and to compare their relative characteristics and also to investigate that which combinations have result in better properties. The precursors of the solid were obtained from different gels of metal nitrates and metal nitrate, metal acetate with glycine used as an oxidizer and a fuel having pH value of 2 and 6, respectively. During our keenly observed processing, it was reproducibly noted that in the case of acetate-nitrate gel the self-propagation temperature was approximately 120(^circ)C-130(^circ)C while in the case of nitrate-nitrate gel the self-propagation temperature was approximately 180(^circ)C-200(^circ)C. The crystal structure, shape and grain size of the nanoparticles had been compared by XRD, SEM and TEM. VSM was used to investigate the magnetic properties of obtained powder. The hysteresis curves indicated the ferromagnetic behavior of the samples at room temperature. FTIR supports the absorption value of octahedral and tetrahedral sites.
采用溶胶-凝胶自燃烧法，采用两种不同的前驱体制备了纳米结构的MgFe (_2) O (_4)粉末。它是缓慢而持续的凝胶形成和随后的燃烧的最终结合。在这项工作中，我们的目标是使用不同的前体合成MgFe纳米颗粒(_2) O (_4)，并比较它们的相对特性，并研究哪种组合具有更好的性能。该固体的前驱体分别由pH值为2和6的金属硝酸盐、金属硝酸盐、金属乙酸和甘氨酸作为氧化剂的不同凝胶制成。在我们仔细观察的过程中，可重复地注意到，在醋酸盐-硝酸盐凝胶的情况下，自传播温度约为120 (^circ) C-130 (^circ) C，而硝酸盐-硝酸盐凝胶的自传播温度约为180 (^circ) C-200 (^circ) C。通过XRD, SEM和TEM比较了纳米颗粒的晶体结构，形状和晶粒尺寸。用VSM对所得粉体的磁性能进行了表征。磁滞曲线反映了样品在室温下的铁磁行为。FTIR支持八面体和四面体的吸收值。
{"title":"Comparative Studies of MgFe(_2)O(_4) Nanoparticles Synthesized using Different Precursors by Sol Gel Auto Combustion Method","authors":"S. Upadhyay, K. Sreenivas","doi":"10.26713/JAMCNP.V2I2.330","DOIUrl":"https://doi.org/10.26713/JAMCNP.V2I2.330","url":null,"abstract":"Nanostructured powder of MgFe(_2)O(_4) was prepared by sol gel auto combustion method using two different precursors. It is an ultimate combination of slow and sustained gel formation and subsequent combustion. In this work, our aim is to synthesize nanoparticles of MgFe(_2)O(_4) using different precursors and to compare their relative characteristics and also to investigate that which combinations have result in better properties. The precursors of the solid were obtained from different gels of metal nitrates and metal nitrate, metal acetate with glycine used as an oxidizer and a fuel having pH value of 2 and 6, respectively. During our keenly observed processing, it was reproducibly noted that in the case of acetate-nitrate gel the self-propagation temperature was approximately 120(^circ)C-130(^circ)C while in the case of nitrate-nitrate gel the self-propagation temperature was approximately 180(^circ)C-200(^circ)C. The crystal structure, shape and grain size of the nanoparticles had been compared by XRD, SEM and TEM. VSM was used to investigate the magnetic properties of obtained powder. The hysteresis curves indicated the ferromagnetic behavior of the samples at room temperature. FTIR supports the absorption value of octahedral and tetrahedral sites.","PeriodicalId":239838,"journal":{"name":"Journal of Atomic, Molecular, Condensate and Nano Physics","volume":"35 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121091497","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2015-12-04DOI: 10.26713/JAMCNP.V2I2.302
Neha Aggarwal, Shweta, A. Bhattacherjee, M. Mohan
We investigate the optical bistable behavior for a weakly interacting two-species Bose-Einstein condensates inside a pumped optical cavity by considering the two possible regimes- the phase mixed regime and the phase segregated regime. We find that the cavity-pump detuning plays a significant role in controlling the threshold of the optical bistability and the constrast between the bistability values depending upon the state we are working in. We also demonstrate the occurence of normal mode splitting in the optical spectrum for both the regimes which further showing the position and amplitude discrepancies in the spectral peaks.
{"title":"Optical Bistability and Normal-Mode Splitting of Two-Species Bose-Einstein Condensates in An Optical Cavity","authors":"Neha Aggarwal, Shweta, A. Bhattacherjee, M. Mohan","doi":"10.26713/JAMCNP.V2I2.302","DOIUrl":"https://doi.org/10.26713/JAMCNP.V2I2.302","url":null,"abstract":"We investigate the optical bistable behavior for a weakly interacting two-species Bose-Einstein condensates inside a pumped optical cavity by considering the two possible regimes- the phase mixed regime and the phase segregated regime. We find that the cavity-pump detuning plays a significant role in controlling the threshold of the optical bistability and the constrast between the bistability values depending upon the state we are working in. We also demonstrate the occurence of normal mode splitting in the optical spectrum for both the regimes which further showing the position and amplitude discrepancies in the spectral peaks.","PeriodicalId":239838,"journal":{"name":"Journal of Atomic, Molecular, Condensate and Nano Physics","volume":"24 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131503071","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2015-12-04DOI: 10.26713/JAMCNP.V2I2.333
Y. Singh, B. Sahoo
We present and compare the results of permanent electric dipole moments (EDMs) of various closed-shell atoms due to the nuclear Schiff moment (NSM) and the tensor-pseudotensor (T-PT) interactions between the atomic nuclei and electrons. In order to highlight the role of electron-correlation effects in obtaining accurate EDM results, we employ a number of relativistic many-body methods including coupled-cluster theory at different degrees of approximation. On combining our results obtained from the relativistic coupled-cluster (RCC) at the levels of singles and doubles excitations (CCSD method) with the available EDM measurements we obtain accurate bounds on the couplings (S) and (C_T) associated with the respective NSM and T-PT interactions. The most precise EDM measurement on (^{199})Hg in combination with our CC results yield limits on the above couplings as (S<1.45 times 10^{-12}|e|)fm(^3) and (C_T < 2.09 times 10^{-9}) respectively. Further combining these bounds with the latest nuclear structure and quantum chromodynamics calculations we infer limits on the strong CP-violating parameter and for the combined up- and down- quark chromo-EDMs as (|bar{theta}| < 1.1 times 10^{-9}) and (|widetilde{d}_u - widetilde{d}_d| < 2.8 times 10^{-26} |e|)cm, respectively.
我们提出并比较了由于核席夫矩(NSM)和原子核与电子之间的张量-伪张量(T-PT)相互作用而导致的各种闭壳原子的永久电偶极矩(EDMs)的结果。为了突出电子相关效应在获得精确电火花加工结果中的作用，我们在不同近似程度上采用了包括耦合簇理论在内的相对论多体方法。结合我们从单激发和双激发水平(CCSD方法)的相对论耦合簇(RCC)得到的结果与可用的EDM测量结果，我们得到了与各自的NSM和T-PT相互作用相关的耦合的精确边界(S)和(C_T)。结合我们的CC结果，对(^{199}) Hg的最精确的电火花加工测量结果分别为(S<1.45 times 10^{-12}|e|) fm (^3)和(C_T < 2.09 times 10^{-9})。进一步将这些边界与最新的核结构和量子色动力学计算相结合，我们推断出强cp违反参数和组合的上、下夸克色edm的极限分别为(|bar{theta}| < 1.1 times 10^{-9})和(|widetilde{d}_u - widetilde{d}_d| < 2.8 times 10^{-26} |e|) cm。
{"title":"Relativistic Many-body Calculations for Electric Dipole Moments in (^{129})Xe, (^{199})Hg, (^{223})Rn, (^{225})Ra and (^{171})Yb Atom","authors":"Y. Singh, B. Sahoo","doi":"10.26713/JAMCNP.V2I2.333","DOIUrl":"https://doi.org/10.26713/JAMCNP.V2I2.333","url":null,"abstract":"We present and compare the results of permanent electric dipole moments (EDMs) of various closed-shell atoms due to the nuclear Schiff moment (NSM) and the tensor-pseudotensor (T-PT) interactions between the atomic nuclei and electrons. In order to highlight the role of electron-correlation effects in obtaining accurate EDM results, we employ a number of relativistic many-body methods including coupled-cluster theory at different degrees of approximation. On combining our results obtained from the relativistic coupled-cluster (RCC) at the levels of singles and doubles excitations (CCSD method) with the available EDM measurements we obtain accurate bounds on the couplings (S) and (C_T) associated with the respective NSM and T-PT interactions. The most precise EDM measurement on (^{199})Hg in combination with our CC results yield limits on the above couplings as (S<1.45 times 10^{-12}|e|)fm(^3) and (C_T < 2.09 times 10^{-9}) respectively. Further combining these bounds with the latest nuclear structure and quantum chromodynamics calculations we infer limits on the strong CP-violating parameter and for the combined up- and down- quark chromo-EDMs as (|bar{theta}| < 1.1 times 10^{-9}) and (|widetilde{d}_u - widetilde{d}_d| < 2.8 times 10^{-26} |e|)cm, respectively.","PeriodicalId":239838,"journal":{"name":"Journal of Atomic, Molecular, Condensate and Nano Physics","volume":"24 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124519496","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2015-12-04DOI: 10.26713/JAMCNP.V2I2.274
S. Pal, S. Maiti, S. Dutta, K. Chattopadhyay
All Solid-state supercapacitors based on pure CuO nanoflakes and CuO@Au heterostructure over carbon cloth were fabricated where directly functioned nanostructure over carbon fiber acts as electrode and detour the necessity of any binder or ancillary materials. High coverage of CuO nanoflakes over entire cylindrical surface of each fiber provide decent electrochemical which nwas further uplifted after Au nanoparticle decoration. Registered electrochemical performance from CuO nanoflakes was found to be 11 F/g at current density 0.5A/g which significantly improved to 26 F/g at the same current density after nanoparticle attachment. Increase in surface area as well as increment of overall conductivity of the hybrid system due to Au nanoparticle attachment may accredit for such performance enrichment. All Solid-state supercapacitors based on pure CuO nanoflakes and CuO@Au heterostructure over carbon cloth were fabricated where directly functioned nanostructure over carbon fib eracts as electrode and detour the necessity of any binder or ancillary materials. High coverage of CuO nanoflakes over entire cylindrical surface of each fiber provide decent electrochemical which was further uplifted after Au nanoparticle decoration. Registered electrochemical performance from CuO nanoflakes was found to be 11 F/g at current density0.5A/g which significantly improved to 26 F/g at the same current density after nanoparticle attachment. Increase in surface area as well as increment of overall conductivity of the hybrid system due to Au nanoparticle attachment may accredit for such performance enrichment.
基于纯CuO纳米薄片和碳布CuO@Au异质结构制备了全固态超级电容器，其中碳纤维上的直接功能纳米结构作为电极，绕过了任何粘合剂或辅助材料的需要。铜纳米薄片在纤维的整个圆柱形表面的高覆盖率提供了良好的电化学性能，并在金纳米颗粒修饰后进一步提高了电化学性能。在0.5A/g电流密度下，CuO纳米片的电化学性能为11 F/g，在相同电流密度下，纳米颗粒附着后的电化学性能显著提高到26 F/g。由于金纳米颗粒的附着，杂化体系的表面积增加以及总电导率的增加可能是这种性能增强的原因。所有基于纯CuO纳米片和CuO@Au异质结构碳布的固态超级电容器都以碳纤维上的直接功能纳米结构作为电极，绕过了任何粘合剂或辅助材料的需要。铜纳米薄片在纤维表面的高覆盖率提供了良好的电化学性能，而金纳米颗粒的修饰进一步提高了电化学性能。在0.5 a /g电流密度下，CuO纳米片的电化学性能为11 F/g，在相同电流密度下，纳米颗粒附着后的电化学性能显著提高到26 F/g。由于金纳米颗粒的附着，杂化体系的表面积增加以及总电导率的增加可能是这种性能增强的原因。
{"title":"Ambient Conditioned, Solution Processed CuO Nanoflakes over Carbon Fabric for Supercapacitor Application: Performance Enhancement via Nanoparticle Attachment","authors":"S. Pal, S. Maiti, S. Dutta, K. Chattopadhyay","doi":"10.26713/JAMCNP.V2I2.274","DOIUrl":"https://doi.org/10.26713/JAMCNP.V2I2.274","url":null,"abstract":"All Solid-state supercapacitors based on pure CuO nanoflakes and CuO@Au heterostructure over carbon cloth were fabricated where directly functioned nanostructure over carbon fiber acts as electrode and detour the necessity of any binder or ancillary materials. High coverage of CuO nanoflakes over entire cylindrical surface of each fiber provide decent electrochemical which nwas further uplifted after Au nanoparticle decoration. Registered electrochemical performance from CuO nanoflakes was found to be 11 F/g at current density 0.5A/g which significantly improved to 26 F/g at the same current density after nanoparticle attachment. Increase in surface area as well as increment of overall conductivity of the hybrid system due to Au nanoparticle attachment may accredit for such performance enrichment. All Solid-state supercapacitors based on pure CuO nanoflakes and CuO@Au heterostructure over carbon cloth were fabricated where directly functioned nanostructure over carbon fib eracts as electrode and detour the necessity of any binder or ancillary materials. High coverage of CuO nanoflakes over entire cylindrical surface of each fiber provide decent electrochemical which was further uplifted after Au nanoparticle decoration. Registered electrochemical performance from CuO nanoflakes was found to be 11 F/g at current density0.5A/g which significantly improved to 26 F/g at the same current density after nanoparticle attachment. Increase in surface area as well as increment of overall conductivity of the hybrid system due to Au nanoparticle attachment may accredit for such performance enrichment.","PeriodicalId":239838,"journal":{"name":"Journal of Atomic, Molecular, Condensate and Nano Physics","volume":"16 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127203660","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2015-12-04DOI: 10.26713/JAMCNP.V2I2.331
Davoud Dastan
Anatase titania thin films were deposited on glass substrates. The substrates were dipped matched dipped into the solution under vigorous stirring. The films were dried at room temperature. Oley amine (OM) was used as a surfactant in the synthesis part and it was vigorously stirred with titanium isopropoxide (TIP) at room temperature. The film samples were annealed at 550(^circ)C for 15 hours. X-ray diffraction (XRD) and Raman spectroscopy were used to study the structural properties of samples. The optical properties of samples were investigated by means of ultraviolet visible (UV vis) spectroscopy. XRD results illustrated the amorphous structure and pure anatase phase of TiO(_2) for as deposited and annealed thin films samples and these results were further confirmed by Raman spectroscopy. UV-visible corroborates the energy band 3.26 eV and 3.22 eV for as prepared and sintered TiO(_2) thin films which simply refers to the change in crystal structure of anatase titania. Furthermore, both samples had high transmittance; almost 78-86%.
{"title":"Nanostructured Anatase Titania Thin Films Prepared by Sol-Gel Dip Coating Technique","authors":"Davoud Dastan","doi":"10.26713/JAMCNP.V2I2.331","DOIUrl":"https://doi.org/10.26713/JAMCNP.V2I2.331","url":null,"abstract":"Anatase titania thin films were deposited on glass substrates. The substrates were dipped matched dipped into the solution under vigorous stirring. The films were dried at room temperature. Oley amine (OM) was used as a surfactant in the synthesis part and it was vigorously stirred with titanium isopropoxide (TIP) at room temperature. The film samples were annealed at 550(^circ)C for 15 hours. X-ray diffraction (XRD) and Raman spectroscopy were used to study the structural properties of samples. The optical properties of samples were investigated by means of ultraviolet visible (UV vis) spectroscopy. XRD results illustrated the amorphous structure and pure anatase phase of TiO(_2) for as deposited and annealed thin films samples and these results were further confirmed by Raman spectroscopy. UV-visible corroborates the energy band 3.26 eV and 3.22 eV for as prepared and sintered TiO(_2) thin films which simply refers to the change in crystal structure of anatase titania. Furthermore, both samples had high transmittance; almost 78-86%.","PeriodicalId":239838,"journal":{"name":"Journal of Atomic, Molecular, Condensate and Nano Physics","volume":"98 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116677120","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2015-12-04DOI: 10.26713/JAMCNP.V2I2.334
R. K. Karn, C. N. Mishra, N. Ahmad, C. Safvan, T. Nandi
We have measured the (rm 1s2s2p ~^4P^0_{5/2})-(rm 1s^22s~^2S_{1/2}) magnetic quadrupole X-ray transition energy in Li-like Fe along with the (rm 1s2s~^3S_1)-(rm 1s^2~^1S_0) transition energy in He-like Fe using multi channel doppler tuned spectrometer. These states have been produced through the interaction of 165 MeV Fe(^{12+}) ion beam with 100 (mu)g/cm(^2) thin carbon foil. Further we have measured the lifetime of (rm 1s2s2p ~^4P^0_{5/2}) level in Li-like Fe. The measured transition energy of (rm 1s2s~^3S_1)-(rm 1s^2~^1S_0) is in good agreement with the available theoretical predictions and experimental measurements, whereas the measurement of (rm 1s2s2p ~^4P^0_{5/2})-(rm 1s^22s~^2S_{1/2}) energy is little lower than the theoretical estimations. However, the measured lifetime of (rm 1s2s2p ~^4P^0_{5/2}) level compares well with the theoretical predictions.
{"title":"Lifetime Measurement of Highly Charged Ions Relevant to Astrophysics","authors":"R. K. Karn, C. N. Mishra, N. Ahmad, C. Safvan, T. Nandi","doi":"10.26713/JAMCNP.V2I2.334","DOIUrl":"https://doi.org/10.26713/JAMCNP.V2I2.334","url":null,"abstract":"We have measured the (rm 1s2s2p ~^4P^0_{5/2})-(rm 1s^22s~^2S_{1/2}) magnetic quadrupole X-ray transition energy in Li-like Fe along with the (rm 1s2s~^3S_1)-(rm 1s^2~^1S_0) transition energy in He-like Fe using multi channel doppler tuned spectrometer. These states have been produced through the interaction of 165 MeV Fe(^{12+}) ion beam with 100 (mu)g/cm(^2) thin carbon foil. Further we have measured the lifetime of (rm 1s2s2p ~^4P^0_{5/2}) level in Li-like Fe. The measured transition energy of (rm 1s2s~^3S_1)-(rm 1s^2~^1S_0) is in good agreement with the available theoretical predictions and experimental measurements, whereas the measurement of (rm 1s2s2p ~^4P^0_{5/2})-(rm 1s^22s~^2S_{1/2}) energy is little lower than the theoretical estimations. However, the measured lifetime of (rm 1s2s2p ~^4P^0_{5/2}) level compares well with the theoretical predictions.","PeriodicalId":239838,"journal":{"name":"Journal of Atomic, Molecular, Condensate and Nano Physics","volume":"60 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131372552","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2015-12-04DOI: 10.26713/JAMCNP.V2I2.322
S. Dhal, A. K. Behera, S. Chatterjee
ZnO nanowires grown by hydrothermal method were exposed to a beam of 50 keV argon ions at a fluence of (1times 10^{16}) ions/cm(^{2}). The surface morphology of the nanowires has been investigated using high resolution electron microscopy. Raman scattering study has been carried out, which shows specific features resulting from argon ion irradiation. The post-irradiated nanowires exhibit high degree of surface roughness of dimension about few nm and tip of each nanowire is sharpened after this irradiation. The combined effect of surface roughening and tip sharpening are expected to enhance the aspect ratio as well as the effective surface-to-volume ratio. We invoked size and curvature dependent sputtering and defect dynamics to explain the observed features. We envisage that such increase of surface area and tip sharpening may enhance applications of these modified ZnO nanowires in the field of catalysis, gas sensing, field emission and photovoltaic.
{"title":"Modification of ZnO Nanowires Induced by Ion Irradiation for Device Applications","authors":"S. Dhal, A. K. Behera, S. Chatterjee","doi":"10.26713/JAMCNP.V2I2.322","DOIUrl":"https://doi.org/10.26713/JAMCNP.V2I2.322","url":null,"abstract":"ZnO nanowires grown by hydrothermal method were exposed to a beam of 50 keV argon ions at a fluence of (1times 10^{16}) ions/cm(^{2}). The surface morphology of the nanowires has been investigated using high resolution electron microscopy. Raman scattering study has been carried out, which shows specific features resulting from argon ion irradiation. The post-irradiated nanowires exhibit high degree of surface roughness of dimension about few nm and tip of each nanowire is sharpened after this irradiation. The combined effect of surface roughening and tip sharpening are expected to enhance the aspect ratio as well as the effective surface-to-volume ratio. We invoked size and curvature dependent sputtering and defect dynamics to explain the observed features. We envisage that such increase of surface area and tip sharpening may enhance applications of these modified ZnO nanowires in the field of catalysis, gas sensing, field emission and photovoltaic.","PeriodicalId":239838,"journal":{"name":"Journal of Atomic, Molecular, Condensate and Nano Physics","volume":"2016 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127450243","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2015-11-30DOI: 10.26713/JAMCNP.V2I2.323
Dipankar Bhattacharyya, A. Ghosh, A. Bandyopadhyay, S. Saha, S. De
Electromagnetically induced transparency (EIT) is experimentally studied in a rubidium vapour cell (without buffer gas, both (^{87})Rb and (^{85})Rb present according to their natural abundance) kept within two-layers of (mu(mu))-metal shields to avoid the effect of Earth's magnetic field on the energy levels of atomic rubidium. An external cavity diode laser (ECDL), used as a low power probe laser, is locked to the hyperfine cross-over peak of (F = 2 rightarrow F' = 2, 3) transitions of (^{87})Rb. The frequency of another ECDL, the pump laser, is set to scan the (F=1 rightarrow F' = 0, 1, 2) transitions of (^{87})Rb. These form the (Lambda)-type six level system. In the V-type system, both the pump and the probe lasers share the same (F = 2) ground level. The probe beam coming out of the cell is detected by a low noise fast photodetector. The resulting spectra show signature of EIT in the "peak" for the (Lambda)-type system and in the "dip" for the V-type system. Numerical calculation based simulated spectra are also compared with the experimental spectra. In both the cases very narrow EIT linewidth ((Gamma_{t} < Gamma)) is observed even at high value of pump Rabi-frequency ((Omega_{c}gg Gamma)). Narrower value of EIT linewidth is due to Doppler averaging phenomena.
{"title":"Comparison of Electromagnetically Induced Transparency (EIT) Spectra for Six-level Lambda (Lambda) and Five-level V-type Systems","authors":"Dipankar Bhattacharyya, A. Ghosh, A. Bandyopadhyay, S. Saha, S. De","doi":"10.26713/JAMCNP.V2I2.323","DOIUrl":"https://doi.org/10.26713/JAMCNP.V2I2.323","url":null,"abstract":"Electromagnetically induced transparency (EIT) is experimentally studied in a rubidium vapour cell (without buffer gas, both (^{87})Rb and (^{85})Rb present according to their natural abundance) kept within two-layers of (mu(mu))-metal shields to avoid the effect of Earth's magnetic field on the energy levels of atomic rubidium. An external cavity diode laser (ECDL), used as a low power probe laser, is locked to the hyperfine cross-over peak of (F = 2 rightarrow F' = 2, 3) transitions of (^{87})Rb. The frequency of another ECDL, the pump laser, is set to scan the (F=1 rightarrow F' = 0, 1, 2) transitions of (^{87})Rb. These form the (Lambda)-type six level system. In the V-type system, both the pump and the probe lasers share the same (F = 2) ground level. The probe beam coming out of the cell is detected by a low noise fast photodetector. The resulting spectra show signature of EIT in the \"peak\" for the (Lambda)-type system and in the \"dip\" for the V-type system. Numerical calculation based simulated spectra are also compared with the experimental spectra. In both the cases very narrow EIT linewidth ((Gamma_{t} < Gamma)) is observed even at high value of pump Rabi-frequency ((Omega_{c}gg Gamma)). Narrower value of EIT linewidth is due to Doppler averaging phenomena.","PeriodicalId":239838,"journal":{"name":"Journal of Atomic, Molecular, Condensate and Nano Physics","volume":"110 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125030444","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2015-11-30DOI: 10.26713/jamcnp.v2i2.321
M. Das, N. K. Gupta
In this work, we have studied the effect of plasma screening on the ground and excited state photoionization cross section ((sigma)) of hydrogenic system. We have considered weakly coupled plasma where the screening of nuclear charge by plasma free electrons is represented by Debye-Huckel potential. Using this potential, radial Schrodinger equation is solved numerically to obtain the bound and free state wave functions, and transition matrix elements. Adaptive step size controlled Runge-Kutta method is used for numerical integration. Use of adaptive method for grid generation ensures lesser computational time as compared to uniform grid system. Using the methodology, we have computed photoionization cross section from (1s) ground state and excited (2p) state of hydrogenic system. Strong enhancements in (sigma) are observed which are generally termed as shape resonances. It is noted that these resonances occur for specific screening values where bound states are pressure ionized to enter the quasi-bound regime. The changes in the phase and amplitude of continuum wave functions also lead to appearance of Cooper minimum in (sigma) of excited (2s) state. We have compared the results with existing theoretical and experimental data wherever they are available.
{"title":"Effect of Debye Plasma on Hydrogenic Photoionization Cross Section","authors":"M. Das, N. K. Gupta","doi":"10.26713/jamcnp.v2i2.321","DOIUrl":"https://doi.org/10.26713/jamcnp.v2i2.321","url":null,"abstract":"In this work, we have studied the effect of plasma screening on the ground and excited state photoionization cross section ((sigma)) of hydrogenic system. We have considered weakly coupled plasma where the screening of nuclear charge by plasma free electrons is represented by Debye-Huckel potential. Using this potential, radial Schrodinger equation is solved numerically to obtain the bound and free state wave functions, and transition matrix elements. Adaptive step size controlled Runge-Kutta method is used for numerical integration. Use of adaptive method for grid generation ensures lesser computational time as compared to uniform grid system. Using the methodology, we have computed photoionization cross section from (1s) ground state and excited (2p) state of hydrogenic system. Strong enhancements in (sigma) are observed which are generally termed as shape resonances. It is noted that these resonances occur for specific screening values where bound states are pressure ionized to enter the quasi-bound regime. The changes in the phase and amplitude of continuum wave functions also lead to appearance of Cooper minimum in (sigma) of excited (2s) state. We have compared the results with existing theoretical and experimental data wherever they are available.","PeriodicalId":239838,"journal":{"name":"Journal of Atomic, Molecular, Condensate and Nano Physics","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116278486","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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