Showing papers in "Indian Journal of Physics in 2012"
TL;DR: In this paper, the amplitude of the nighttime VLF signals anomalously fluctuated 4 days before the Indian Navy station VTX received an earthquake of magnitude 7.4 at Southwestern Pakistan (latitude 28.9°N, longitude 64°E).
Abstract: We have presented the result of the analysis of the nighttime VLF signals transmitted from the Indian Navy station VTX (latitude 8.43°N, longitude 77.73°E) at 19.2 kHz and received at Kolkata (latitude 22.57°N, longitude 88.24°E). On 18th January, 2011 an earthquake of magnitude 7.4 occurred at Southwestern Pakistan (latitude 28.9°N, longitude 64°E). We have analyzed the nighttime VLF signals for 2 weeks around 18th of January, 2011 to see if there have been any precursory effects of this earthquake. We have found that the amplitude of the nighttime VLF signals anomalously fluctuated 4 days before the earthquake. This agrees well with our previous findings based on the analysis of 1 year of earthquake data.
48 citations
TL;DR: In this article, the amplitude variation of the diurnal signal at each of these receiving stations in winter and summer was compared and the results generally agree with the signal shapes obtained using the long wave propagation capability code based on mode propagation through the Earth-ionosphere cavity.
Abstract: We have carried out 2 week-long campaigns in Indian winter and summer to study VLF signals from the Indian navy transmitter (VTX) operating at 18.2 kHz. We have used more than a dozen of receivers scattered throughout the Indian sub-continent in each of these campaigns. To our knowledge, this is the largest campaign of its kind in this region. The propagation paths range from 500 km to almost 3,000 km covering an area of about 4 million sq km. We have presented the results of the amplitude variation of the diurnal signal at each of these receiving stations in winter and summer and compare them. We have clearly found the non-reciprocity of the east to west and west to east propagation. Our results generally agree with the signal shapes obtained using the long wave propagation capability code based on mode propagation through the Earth-ionosphere cavity.
45 citations
TL;DR: In this paper, the robustness and fragility of scale-free networks under topologically biased failure (degree-dependent percolation) was studied. And a clear division between robust regime and fragile regime can be extracted based on natural connectivity by tuning the bias exponent α.
Abstract: The natural connectivity is recently reported as a novel spectral measure of robustness in complex networks. It has a clear physical meaning and a simple mathematical formulation. In this article, based on the natural connectivity, we study the robustness and fragility of scale-free networks under topologically biased failure (degree-dependent percolation). The probability p
ij
that an edge between nodes i and j remains intact is assumed to depend on the degrees k
i
and k
j
through p
ij
∝ (k
i
k
j
)−α. We show that a clear division between robust regime and fragile regime can be extracted based on natural connectivity by tuning the bias exponent α. The theory is found in good accordance with simulations.
38 citations
TL;DR: In this paper, the effect of constant effective mass and position-dependent effective mass on the optical properties of a spherical quantum dot has been studied, and the intersubband optical absorption coefficient and the refractive index changes are obtained using both a constant effectivemass and position dependent effective mass.
Abstract: In this paper, the effect of constant effective mass and position-dependent effective mass on the optical properties of a spherical quantum dot has been studied. For this purpose, the intersubband optical absorption coefficient and the refractive index changes are obtained using both a constant effective mass and position-dependent effective mass. According to the results obtained from the present work, we find that spatially varying electron effective mass plays an important role in obtaining the intersubband optical absorption coefficients and refractive index changes in the finite and infinite quantum dots.
34 citations
TL;DR: In this article, the extended tanh-method was used for constructing exact traveling wave solutions of the nonlinear diffusion reaction equation with quadratic, cubic and quartic nonlinearities.
Abstract: In this work, using a generalized ansatz, we have presented the extended tanh-method for constructing a variety of exact traveling wave solutions of the nonlinear diffusion reaction equation with quadratic, cubic and quartic nonlinearities. We have examined the density independent and dependent nonlinear diffusion reaction equation with a convective flux term and successfully obtain some new and more general solutions like kink and antikink solitons. The present work confirms the significant features of the employed method and shows the variety of the obtained solutions.
31 citations
TL;DR: In this paper, Nanocrystalline lead sulphide thin films were deposited on clean glass substrates by chemical bath deposition technique using lead acetate and thiourea as Pb+2 and S−2 ions source respectively.
Abstract: Nanocrystalline lead sulphide thin films were deposited on clean glass substrates by chemical bath deposition technique using lead acetate and thiourea as Pb+2 and S−2 ions source respectively. Films of five different molarities (0.05 M–0.150 M) of same pH value 10.5 were prepared at 318 K. Characterization was carried out using X-ray diffraction (XRD), X-ray fluorescence, scanning electron microscopy, optical absorption and electrical conductivity measurements. Average crystallite size calculated from the XRD spectra using Scherrer’s formula were between 13 and 18 nm. The optical absorption spectra shifted towards the lower wavelength. The band gap energy of 2.13–2.44 eV was determined from the optical absorption spectra. The electrical conductivity measured using two co-planar Aluminium electrodes was found to increase with increase in temperature showing semiconducting nature of the films. The electrical conductivity at room temperature was found to be of the order of 10−4 Ω−1 cm−1.
31 citations
TL;DR: In this paper, the expansion method and its generalized version have been employed for obtaining a variety of exact traveling wave solutions of the nonlinear diffusion reaction equation with quadratic and cubic nonlinearities.
Abstract: In the present work, the \((\frac{G^\prime}{G})\)-expansion method and its generalized version have been employed for obtaining a variety of exact traveling wave solutions of the nonlinear diffusion reaction equation with quadratic and cubic nonlinearities. We have examined the density independent nonlinear diffusion reaction equation with a convective flux term and successfully have obtained some new and more general solutions in terms of Jacobi elliptic functions. The work highlights the significant features of the employed methods and shows the variety in the obtained solutions.
28 citations
TL;DR: In this paper, a uniform SnO2/TiO2 core shell nanocomposite was prepared by sol gel processing, and the sensing properties of all as-fabricated sensors were investigated with different ethanol concentrations and operating temperatures.
Abstract: TiO2 and SnO2 are the well-known sensing materials with a good thermal stability of the former and a high sensitivity of the latter In this article, a uniform SnO2/TiO2 core shell nanocomposite was prepared by sol gel processing The sensing properties of all as-fabricated sensors were investigated with different ethanol concentrations and operating temperatures At the region of low operating temperature (below 220°C), the sensors based on SnO2/TiO2 core shell nanocomposite show improvements in sensing behavior This result shows the prospect of the stable gas sensors at working temperatures below 220°C
28 citations
TL;DR: In this article, a spatially homogeneous and anisotropic Bianchi-II cosmological models representing massive strings in normal gauge for Lyra's manifold by applying the variation law for generalized Hubble's parameter that yields a constant value of deceleration parameter.
Abstract: The present study deals with a spatially homogeneous and anisotropic Bianchi-II cosmological models representing massive strings in normal gauge for Lyra’s manifold by applying the variation law for generalized Hubble’s parameter that yields a constant value of deceleration parameter. The variation law for Hubble’s parameter generates two types of solutions for the average scale factor, one is of power-law type and other is of the exponential form. Using these two forms, Einstein’s modified field equations are solved separately that correspond to expanding singular and non-singular models of the universe respectively. The energy-momentum tensor for such string as formulated by Letelier (Phys Rev D 28:2414, 1983) is used to construct massive string cosmological models for which we assume that the expansion (θ) in the model is proportional to the component σ
1
1
of the shear tensor σ
. This condition leads to A = (BC)
m
, where A, B and C are the metric coefficients and m is proportionality constant. Our models are in accelerating phase which is consistent with the recent observations. It has been found that the displacement vector β behaves like cosmological term $$\Uplambda$$
in the normal gauge treatment and the solutions are consistent with recent observations of SNe Ia. It has been found that massive strings dominate in the decelerating universe, whereas strings dominate in the accelerating universe. Some physical and geometric behaviours of these models are also discussed.
27 citations
TL;DR: In this article, a physical example of hyperstructures associated with the elementary particle physics, Leptons, is presented. But the main purpose of this paper is to provide, for the first time, a physical representation of the Lepton set and the interactions between its members.
Abstract: Algebraic hyperstructures represent a natural extension of classical algebraic structures in which the composition of two elements of a set is a set, instead of an element. The main purpose of this paper is to provide, for the first time, a physical example of hyperstructures associated with the elementary particle physics, Leptons. We have considered this important group of the elementary particles and shown that this set along with the interactions between its members can be described by the algebraic hyperstructures.
26 citations
TL;DR: In this article, a mathematical formalism of force balance and self assembly along with a quantum mechanical algorithmic approach for avoiding uncertainty relations in a limited range, where tiny nano particles constitute an elementary unit.
Abstract: The molecular nanotechnology is the concept of functional mechanical system at the molecular scale, i.e., machines at the molecular scale, designed and built atom by atom. This idea along with self recognition (self assembly) can be used in the development of intelligent nanoparticles (NPs). In this paper we present a mathematical formalism of force balance and self assembly along with a quantum mechanical algorithmic approach for avoiding uncertainty relations in a limited range, where tiny nano particle (1–100 nm), constitute an elementary unit. We explain the natural self organization, where, the system organizes itself, but there is no known agent inside the system doing the organizing. Thiol, aspartic acid, citrate and bovine serum albumin capped gold NPs were synthesised in the laboratory with potentially useful size and shape dependent properties. We used colloidal method for synthesis of NPs confinement at 2, 5, 10 and 20 nm. The particle shape contours were measured by transmission electron microscope with high resolution field emission scanning electron microscope (FE-SEM, FEI Quanta 200F). AFM (AFM-STM, Ntegra Ts-150) study was performed to see the surface topology and confinement. SPR spectra study including pH stability analysis is used to study the properties of quantum confinement.
TL;DR: In this article, the influence of substrate bias voltage on the structural, surface morphological, electrical and optical properties has been studied systematically and the crystallite size of the films increases with the increase of the bias voltage up to −60 V.
Abstract: Cuprous oxide films have been prepared on glass substrates by sputtering of metallic copper target in an oxygen partial pressure of 2 × 10−2 Pa under different substrate bias voltages in the 0 to −100 V range employing RF magnetron sputtering technique. The influence of substrate bias voltage on the structural, surface morphological, electrical and optical properties has been studied systematically. The crystallite size of the films increases with the increase of substrate bias voltage up to −60 V. The films formed at substrate bias voltage of −60 V show low electrical resistivity of 12 Ω cm, larger crystallite size of 35 nm and optical band gap of 2.40 eV.
TL;DR: In this paper, a high energy planetary ball mill (Retsch PM 400/2) was used to synthesize zinc sulphide (ZnS) by using zinc acetate and sodium sulphide as source materials.
Abstract: Nanosized zinc sulphide (ZnS) was synthesized by the mechanochemical route using zinc acetate and sodium sulphide as source materials in a high energy planetary ball mill (Retsch PM 400/2) for 30–90 min at rotation speed of 300 rpm and vial rotation speed of 600 rpm with ball to powder ratio 5:1. The milled powder was washed with methanol to remove impurity and heat treated at 100–400 °C. ZnS nanoparticles then characterized by using X-ray diffraction (XRD), field emission scanning electron microscope (FESEM), UV–Vis–NIR spectrophotometer and fluorescence spectrophotometer. The crystallite size of the synthesized ZnS nanoparticles is found to be in 3–9 nm range. FESEM morphology shows the formation of nanostructure of ZnS samples. The value of optical band gap has been found to be in the range 3.87–4.66 eV. Room temperature photoluminescence spectrum of ZnS samples exhibit a blue emission peaked at 466 nm under UV excitation.
TL;DR: In this article, it is observed that for FeCl3 and iodine (except 120 min) doped samples there is an increase in crystallinity due to doping and crystallinity increases with increase in dopant concentration.
Abstract: Polythiophene (PT) was chemically synthesized, undoped using aqueous ammonia and then re-doped using FeCl3 as well as iodine. Doping concentration was changed by changing the duration of doping process. FTIR results indicate the complex formation between PT and each of the dopants. Elemental analysis of FeCl3 doped samples show that as the duration increases concentration of Fe+ ions increases. In case of iodine doped samples atom equivalent of iodine per thiophene unit increases with doping duration. XRD analysis has been used to calculate crystallinity. It is observed that for FeCl3 and iodine (except 120 min) doped samples there is increase in crystallinity due to doping and crystallinity increases with increase in dopant concentration. TGA analysis shows that FeCl3 doped samples are thermally stable compared to iodine doped samples. Results of DTA as well as DSC indicate that Tg values vary with dopant as well as with dopant concentrations. Reduction in Tg values for all FeCl3 doped samples indicate that FeCl3 acts as plasticizer in PT. In iodine doped samples for low values of dopant concentrations Tg increases indicating anti-plasticizer effect whereas for high concentration of iodine, there is decrease in Tg value indicating plasticizer effect of iodine in PT.
TL;DR: In this article, conditions for the existence of dust acoustic solitary waves have been investigated on the nonlinear, unmagnetized homogeneous dusty plasma with variable dust charge and an arbitrary streaming ion beam.
Abstract: Conditions for the existence of dust acoustic solitary waves have been investigated on the nonlinear, unmagnetized homogeneous dusty plasma with variable dust charge and an arbitrary streaming ion beam. The Sagdeev’s pseudopotential has been derived in terms of ud, the dust fluid flow velocity. It is found that there exists a critical value of \(u_{d_{0}} \)(≠0), the value of ud at which (ud′)2 = 0, beyond which the solitary waves cease to exist. This critical value of ud depends on other parameters like dust temperature, etc.
TL;DR: In this paper, the effects of the ratio of electron temperature to ion temperature on the phase shift have also been studied and it is found that the presence of nonthermal ions play a significant role on the collision of dust acoustic solitary waves.
Abstract: The head-on collision of dust acoustic solitary waves in a three-component unmagnetized dusty plasma with Boltzmann distributed electrons, nonthermal ions and negatively charged dust grains has been investigated using the extended Poincare-Lighthill-Kuo method. The effects of the ratio of electron temperature to ion temperature on the phase shift have also been studied. It is found that the presence of nonthermal ions play a significant role on the collision of dust acoustic solitary waves. There are real implementation of present results in different regions of space, viz cometary tails, upper and lower mesosphere, Jupiter’s magnetosphere, etc.
TL;DR: The electronic structure of Ge, GaP and InP semiconductors under hydrostatic pressure based on the empirical pseudopotential method has been reported in this article, where pressure coefficients, pressure dependent form factors, of the main band gaps at the symmetry points in the Brillouin zone have been calculated.
Abstract: The electronic structure of Ge, GaP and InP semiconductors under hydrostatic pressure based on the empirical pseudopotential method have been reported. The pressure coefficients, pressure dependent form factors, of the main band gaps at \( \underline{\Upgamma } ,\;\underline{\text{X}} \) and \( \underline{\text{L}} \) symmetry points in the Brillouin zone have been calculated. We have found that most of the values of the electronic energy bands were more sensitive to the pressure dependent form factors associated with the reciprocal lattice vectors of \( \left| {\Updelta \underline{\underline{{\mathbf{G}}}} } \right|^{2} = 11 \) than any other value. Our calculations for the energy gaps of the semiconductors under investigation at different pressures have been found to be in excellent agreement with available experimental data.
TL;DR: In this article, the propagation of ion acoustic waves in plasmas containing superthermal electrons, thermal positrons and high relativistic ions is investigated, and it is shown that the Korteweg-de Vries (KdV) equation describes the nonlinear waves in such plamas.
Abstract: Propagation of ion acoustic waves in plasmas containing superthermal electrons, thermal positrons and high relativistic ions is investigated. It is shown that the Korteweg-de Vries (KdV) equation describes the nonlinear waves in such plasmas. The effects of relativistic ions and superthermal electrons on the soliton identifications are discussed.
TL;DR: In this paper, the homotopy perturbation method (HPM) is proposed to solve the series solution of the Duffing's equation, which yields a series solution.
Abstract: In this paper, the homotopy perturbation method (HPM) is proposed to solve Duffing’s equation, which yields a series solution. Then, Pade approximation yielding the analytic approximate solution with fast convergence rate and high accuracy is applied for the series solution derived from the HPM. To illustrate the ability and the reliability of the method, two examples are provided. The results reveal that the method is very effective and simple.
TL;DR: In this paper, the relative complex dielectric function, electric modulus, alternating current electrical conductivity and complex impedance behavior of aqueous poly(ethylene oxide) (PEO) and poly(vinyl pyrrolidone)(PVP) blend with montmorillonite (MMT) clay nano-platelets as colloidal suspensions have been investigated over the frequency range 20 Hz to 1 MHz at 15, 30 and 45°C.
Abstract: The relative complex dielectric function, electric modulus, alternating current electrical conductivity and complex impedance behaviour of aqueous poly(ethylene oxide) (PEO) and poly(vinyl pyrrolidone) (PVP) blend with montmorillonite (MMT) clay nano-platelets as colloidal suspensions have been investigated over the frequency range 20 Hz to 1 MHz at 15, 30 and 45 °C. The direct current ionic conductivity and real part of permittivity of the hydrocolloids have increased whereas electrode polarization relaxation time has decreased with the increase of MMT concentration, and these dielectric parameters have significantly varied with change of the temperature. The hydrogen bond complex formation between PEO, PVP and dispersed MMT nano-platelets in aqueous solutions has been discussed. The correlation between complex structures and the dielectric parameters of these materials have been confirmed.
TL;DR: In this article, the authors compared the results from the hadron resonance gas (HRG) model with the available experimental data and found that the overall energy-dependence is non-monotonic.
Abstract: We have studied the event-by-event dynamical fluctuations of some particle yield ratios at various incident energies. We have assumed that the particle production in the final state is due to chemical equilibrium processes. We have compared the results from the hadron resonance gas (HRG) model with the available experimental data. At energies up to SPS, the HRG model can very well reproduce the experimentally measured fluctuations. To reproduce RHIC results, the quark phase space occupancy parameter is allowed to vary. Furthermore, we have made predictions for the dynamical fluctuations of strange and non-strange particle ratios. We have found that the overall energy-dependence is non-monotonic. We have also found that the fluctuations strongly depend on the various species of particle ratios.
TL;DR: In this paper, the authors derived the Korteweg-deVries-Burger equation (KdV-Burgers) using small amplitude perturbation expansion method to study the nonlinear propagation of the DASWs.
Abstract: Dust acoustic shock waves (DASWs) have been studied in an unmagnetized dusty plasma system consisting of coupled negatively charged dust and ions obeying superthermal distribution. Korteweg-deVries-Burger equation (KdV-Burgers) has been derived using small amplitude perturbation expansion method to study the nonlinear propagation of the DASWs. The behavior of the shock waves in the plasma has been investigated. It is found that the coefficients of the KdV-Burgers equation are significantly modified by k-parameter (k is a spectral index for superthermal distribution).
TL;DR: An adaptive function projective synchronization scheme between two entirely different fractional-order chaotic systems with uncertain parameters has been addressed, and the parameter update law is gained.
Abstract: An adaptive function projective synchronization scheme between two entirely different fractional-order chaotic systems with uncertain parameters has been addressed. The adaptive controller has been designed, and the parameter update law is also gained. One example has been presented to demonstrate the effectiveness of the proposed method.
TL;DR: In this article, a simple chemical method using polyvinyl alcohol as matrix X-ray diffraction has been used for determining structures of ZnS nanocrystals along with high resolution transmission electron microscopy.
Abstract: ZnS nanoparticles within the range 3–6 nm have been synthesized by simple chemical method using polyvinyl alcohol as matrix X-ray diffraction has been used for determining structures of ZnS nanocrystals along with high resolution transmission electron microscopy For all deposited films the preferential orientation is along (111) direction with some other planes (220) and (311) The grain sizes of the particles have been calculated using both Scherrer’s formula and Williamson–Hall plot The lattice constant ‘a’ have been obtained using Nelson–Riley plot The average internal stress, microstrain, dislocation density and degree of preferred orientation in the films are calculated and correlated with molarities of the films
TL;DR: In this article, the effects of space weather on ground-based technology mostly occur due to the varying geomagnetic field during geOMagnetic storms, producing geomagnetically induced current (GIC).
Abstract: The effects of space weather on ground based technology mostly occur due to the varying geomagnetic field during geomagnetic storms, producing geomagnetically induced current (GIC). Space weather storms involve intense and rapidly varying electric currents in the ionosphere, which create geoelectric and geomagnetic fields at the Earth’s surface. In this study we have investigated some intense geomagnetic storms: September 18th, 2000; March 31th, 2001; October 21st, 2001; November 6th and 24th, 2001; October 29th and 31st, 2003 and November 9th, 2004. The electric field for each day has been computed using ground conductivity and geomagnetic recordings. The conductivity models are determined by least square fit between the observed and predicted GIC values. Our results show that GIC are strongly correlated with the geoelectric field, and also with eastward and westward auroral electrojet indices and time derivatives of the horizontal geomagnetic field. Root mean square error statistical test has been employed to evaluate the accuracy of the models used.
TL;DR: In this article, the dispersive topological solitons that are governed by the Boussinesq-sine-Gordon equation were reported and the ansatz method was used to integrate the perturbed dispersive double sine Gordon equation.
Abstract: In this paper, we report the dispersive topological solitons that are governed by the dispersive sine-Gordon equation and it’s type that is also known as Boussinesq-sine-Gordon equation. The $$G^{\prime}/G$$
-expansion method and the exp-function method are adopted as the necessary tools to carry out the integration. Finally, the ansatz method is utilized to integrate the perturbed dispersive double sine-Gordon equation. The parameter domain restrictions naturally fall out during the process of these soliton solutions retrieval.
TL;DR: In this article, the effect of viscous drag and surface tension on the nonlinear two fluid interfacial structures induced by Rayleigh-Taylor instability and Richtmyer-Meshkov instability have been investigated.
Abstract: The effect of viscous drag and surface tension on the nonlinear two fluid interfacial structures induced by Rayleigh–Taylor instability and Richtmyer–Meshkov instability have been investigated. Viscosity and surface tension play important roles on the fluid instabilities. It is seen that the magnitude of the suppression of the terminal growth rate of the tip of the bubble height depends only on the viscous coefficient of the upper (denser) fluid through which the bubble rises. However, in regard to spike it is shown that in an inviscid fluid spike does not remain terminal but approaches a free fall $$\sim \frac{1}{2} \gamma g t^{2}$$
(γ is of order unity) as the Atwood number A increases. In this respect there exits qualitative agreement with simulation result and also with some earlier theoretical results. Viscosity reduces the free fall velocity appreciably and with increasing viscosity tends to make it terminal. Results obtained from numerical integration of the relevant nonlinear equations describing the temporal development of the spike support the foregoing observations.
TL;DR: In this article, the authors reviewed experiments that test the isotropy of the speed of light in one-way and two-way approaches and discussed the level of experimental verification that these experiments provide.
Abstract: As we approach the 125th anniversary of the Michelson–Morley experiment in 2012, we have reviewed experiments that test the isotropy of the speed of light. Previous measurements are categorized into one-way (single-trip) and two-way (round-trip averaged or over closed paths) approaches and the level of experimental verification that these experiments provide is discussed. The isotropy of the speed of light is one of the postulates of the special theory of relativity and, consequently, this phenomenon has been subject to considerable experimental scrutiny. Here, we have tabulated significant experiments performed since 1881 and attempt to indicate a direction for future investigation.
TL;DR: In this paper, thin films of varying thicknesses were prepared on glass substrate by chemical bath deposition technique at room temperature in which selenium dioxide is source of Se2− while cadmium acetate is the source of Cd2+ ions.
Abstract: Cd–Se thin films of varying thicknesses were prepared on glass substrate by chemical bath deposition technique at room temperature in which selenium dioxide is source of Se2− while cadmium acetate is source of Cd2+ ions. Ammonia was used as complexing agent. Nickel doping is achieved by adding Ni(NO3)2 solution to the bath. Approximate thickness was measured by gravimetric method. Band gap of the films was determined by measuring percent transmittance of film at various wavelengths. The band gap and thickness of the film were found to increase with increase of Ni concentration in films. The composition and structural characterization was carried out by using EDAX and SEM.
TL;DR: In this article, the mid-infrared spectrum of aniline vapour was investigated and the IR spectrum of the compound in solid nitrogen matrix under a cryogenic condition was measured for the first time.
Abstract: The mid-infrared spectrum of aniline vapour is reinvestigated, and the IR spectrum of the compound in solid nitrogen matrix under a cryogenic condition is measured for the first time. A thorough assignment of many features of the vapour spectrum, particularly those related to amine inversion mode, is suggested. By use of PGOPHER fitting of the rotational band contours in the fingerprint region, the amine inversion tunnelling splitting at v = 1 level of NH2 scissoring and C–N bending vibrations in the vapour spectrum are identified. Our analysis reveals that excitation of one quantum of NH2 scissoring results in lowering of the tunnelling barrier, whereas, the barrier is increased upon excitation of the C–N bending. Comparison of the spectra recorded in nitrogen and argon matrixes reveal that the former hinders the NH2 inversion and consequently, transitions corresponding to higher quanta of this mode are absent.