High resolution analysis of the ethylene-1-C spectrum in the 8.4-14.3-μm region

Fourier transform spectra of mono-¹³C ethylene have been recorded in the 8.4-14.3-μm spectral region (700-1190 cm⁻¹) using a Bruker 120 HR interferometer at a resolution of 0.0017 cm⁻¹ allowing the extensive study of the set of resonating states {10¹, 8¹, 7¹, 4¹, 6¹}. Due to the high resolution available as well as the extended spectral range involved in this study, a much larger set of line assignments are now available. The present analysis has lead to the determination of more accurate spectroscopic constants, including interaction constants, than were obtained in earlier studies. In particular, the following band centers were derived: ν₀(ν₁₀) = 825.40602(30) cm⁻¹, ν₀(ν₈) = 932.19572(15) cm⁻¹, ν₀(ν₇) = 937.44452(10) cm⁻¹, ν₀(ν₄) = 1025.6976(14) cm⁻¹. Finally a synthetic spectrum was generated leading to the assignment of a number of ¹³C¹²CH₄ lines observed in an earlier heterodyne spectroscopic study.     

Analysis of rotational structure in the high-resolution infrared spectrum and assignment of vibrational fundamentals of butadiene-2,3-C2

The 2,3-¹³C₂ isotopomer of butadiene was synthesized, and its fundamental vibrational fundamentals were assigned from a study of its infrared and Raman spectra aided with quantum chemical predictions of frequencies, intensities, and Raman depolarization ratios. For two C-type bands in the high-resolution (0.002 cm⁻¹) infrared spectrum, the rotational structure was analyzed. These bands are for ν₁₁ (a_u) at 907.17 cm⁻¹ and for ν₁₂ (a_u) at 523.37 cm⁻¹. Ground state and upper state rotational constants were fitted to Watson-type Hamiltonians with a full quartic set of centrifugal distortion constants and two sextic ones. For the ground state, A₀ = 1.3545088(7) cm⁻¹, B₀ = 0.1469404(1) cm⁻¹, and C₀ = 0.1325838(2)  cm⁻¹. The small inertial defects of butadiene and two ¹³C₂ isotopomers, as well as for five deuterium isotopomers as previously reported, confirm the planarity of the s-trans rotamer of butadiene.     

Laser spectroscopic monitoring of gas emission and measurements of the C/C isotope ratio in CO2 from a wood-based combustion

We report on the application of a compact and field-deployable instrument, based on a continuous-wave fiber-coupled Telecom external cavity diode laser, to measure the ¹³C/¹²C isotope ratio in CO₂ from a wood-based combustion. Carbon dioxide, the most important greenhouse gas, is a major product of combustion. The measurements of the ¹³C/¹²C isotopic ratio in CO₂ from combustion emission permit one to identify the CO₂ source and to study the temporal and spatial variations of pollution in the atmosphere. The average value of the ¹³CO₂/¹²CO₂ ratio is found to be (1.1011±0.0024)%. The corresponding δ-value relative to PDB standard is (−20.17±2.14)‰, which is in good agreement with the typical value of (−25±2)‰ for wood. Simultaneous monitoring of multiple species from gas emission has been performed using direct-absorption spectroscopy. The concentrations of C₂H₂, CO, CO₂ and H₂O were determined on the basis of integrated absorbance measured by least-squares fitting a Voigt lineshape to experimental absorption spectra.     

Diode laser absorption spectra of HCCD and HCCD at 6500 cm

The absorption spectra of H¹²C¹³CD and H¹³C¹²CD have been observed at high resolution between 6480 and 6610 cm⁻¹ using an external cavity diode laser. The strong 2ν₁ band has been observed for each species using a sample enriched in deuterium at natural abundance of ¹³C. Rotational analyses reveal bands of both species to be essentially unperturbed. Centers of unblended lines are determined with an accuracy of approximately 10 MHz.     

Polyethylene terephthalate (PET) bulk film analysis using C60, Au3, and Au primary ion beams

The damage characteristics of polyethylene terephthalate (PET) have been studied under bombardment by C₆₀⁺, Au₃⁺ and Au⁺ primary ions. The observed damage cross-sections for the three ion beams are not dramatically different. The secondary ion yields however were significantly enhanced by the polyatomic primary ions where the secondary ion yield of the [M + H]⁺ is on average 5× higher for C₆₀⁺ than Au₃⁺ and 8× higher for Au₃⁺ than Au⁺. Damage accumulates under Au⁺ and Au₃⁺ bombardment while C₆₀⁺ bombardment shows a lack of damage accumulation throughout the depth profile of the PET thick film up to an ion dose of ∼1 × 10¹⁵ ions cm⁻². These properties of C₆₀⁺ bombardment suggest that the primary ion will be a useful molecular depth profiling tool.     

High sensitivity cw-cavity ringdown and Fourier transform absorption spectroscopies of CO2

The absorption spectrum of ¹³CO₂ has been recorded by cw-cavity ringdown spectroscopy with a new set up based on fibered DFB lasers. By using a series of 31 DFB lasers, the spectrum of carbon dioxide could be recorded in the 6130-6750 cm⁻¹ region with a typical sensitivity of 5 × 10⁻¹⁰ cm⁻¹. The spectrum has also been recorded between 4400 and 8500 cm⁻¹ with a Fourier transform spectrometer associated with a multi-pass cell (maximum path length of 105 m). The new observations obtained both by FTS and CRDS represent a significant extension of the available data. For instance, more than 4000 line positions were measured and assigned in the CRDS spectrum while only 232 line positions are listed in the HITRAN database. Altogether, the band by band analysis has led to the determination of the rovibrational parameters of 65, 7, and 24 bands for the ¹³C¹⁶O₂, ¹⁶O¹³C¹⁷O, and ¹⁶O¹³C¹⁸O isotopomers, respectively. As some observed line positions show significant deviations from the predictions of the effective Hamiltonian model, the new observed line positions were gathered with the data available in the literature to refine the set of effective Hamiltonian parameters of the ¹³C¹⁶O₂ isotopic species. The refined set of 96 effective Hamiltonian parameters reproduces more than 14 650 line positions of ¹³C¹⁶O₂ with an RMS=0.002 cm⁻¹. A detailed comparison with the line positions retrieved from Venus spectra and the line list provided by HITRAN is also presented and discussed.     

The ν12 band of ethylene-1-C (CCH4) by high-resolution FTIR spectroscopy

The Fourier transform infrared (FTIR) spectrum of the ν₁₂ fundamental band of ethylene-1-¹³C (or ¹³C¹²CH₄) was recorded with an unapodized resolution of 0.0063 cm⁻¹ in the wavenumber region of 1360-1520 cm⁻¹. Rovibrational constants for the upper state (ν₁₂ = 1) up to five quartic and two sextic centrifugal distortion terms were derived for the first time by assigning and fitting a total of 879 infrared transitions using a Watson’s A-reduced Hamiltonian in the I^r representation. The root-mean-square deviation of the fit was 0.00066 cm⁻¹. The ground state rovibrational constants were also determined by a fit of 523 combination-differences from the present infrared measurements, with a rms deviation of 0.00090 cm⁻¹. The A-type ν₁₂ band which is centred at 1439.34607 ± 0.00004 cm⁻¹ was found to be relatively free from local frequency perturbations. From the ν₁₂ = 1 rovibrational constants obtained, the inertial defect Δ₁₂ was found to be 0.242826 ± 0.000002 μŲ.     

Characterisation of human hair surfaces by means of static ToF-SIMS: A comparison between Ga and C60 primary ions

This study deals with the secondary ion yield improvement induced by using C₆₀⁺ primary ions instead of Ga⁺ ones to characterize human hair surfaces by ToF-SIMS. For that purpose, a bunch of hair fibres has been analysed with both ion sources. A high improvement is observed for the detection of amino acids with C₆₀⁺ primary ions as compared to Ga⁺ ions. As an example, a yield enhancement factor greater than 3000 is found for the CNO⁻ peak. A similar gain is observed for the positive secondary ions characteristic of the amino acids. Most of the atomic ions, such as Ca⁺, O⁻ and S⁻, constitute minor peaks with C₆₀⁺ ions while they often dominate the spectrum in the case of Ga⁺ ions. However, with the C₆₀⁺ source, a series of inorganic combination peaks with the elements Ca, S and O are observed in the positive spectra (i.e. HCaSO₄⁺), while they are marginal with the Ga⁺ source. For the mass range beyond 100 m/z and in both polarities, the hair fingerprints are similar with both sources. In average, for a comparable number of primary ions per spectrum, the C₆₀⁺ ion source gives intensities between two and three orders of magnitude higher than the Ga⁺ one.     

Simultaneous measurement of neuronal and glial metabolism in rat brain in vivo using co-infusion of [1,6-C2]glucose and [1,2-C2]acetate

In this work the feasibility of measuring neuronal-glial metabolism in rat brain in vivo using co-infusion of [1,6-¹³C₂]glucose and [1,2-¹³C₂]acetate was investigated. Time courses of ¹³C spectra were measured in vivo while infusing both ¹³C-labeled substrates simultaneously. Individual ¹³C isotopomers (singlets and multiplets observed in ¹³C spectra) were quantified automatically using LCModel. The distinct ¹³C spectral pattern observed in glutamate and glutamine directly reflected the fact that glucose was metabolized primarily in the neuronal compartment and acetate in the glial compartment. Time courses of concentration of singly and multiply-labeled isotopomers of glutamate and glutamine were obtained with a temporal resolution of 11 min. Although dynamic metabolic modeling of these ¹³C isotopomer data will require further work and is not reported here, we expect that these new data will allow more precise determination of metabolic rates as is currently possible when using either glucose or acetate as the sole ¹³C-labeled substrate.     

Highly sensitive absorption spectroscopy of carbon dioxide by ICLAS-VeCSEL between 8800 and 9530 cm

The absorption spectrum of carbon dioxide has been studied between 8800 and 9530 cm⁻¹ by intracavity laser absorption spectroscopy based on a vertical external cavity surface emitting lasers (VeCSEL). Previous laboratory spectra at high resolution were nearly absent in the considered spectral region. Experiments were carried with natural carbon dioxide and with ¹³C enriched carbon dioxide leading to the determination of the rovibrational parameters of a total of 15 very weak vibrational transitions, including two bands of the ¹⁶O¹³C¹⁸O isotopologue. The observed transitions are assigned to components of the 2ν₁ + 3ν₃ triad and of the much weaker 5ν₁ + ν₃ hexad. Our measured line positions are found in excellent agreement with the predictions of the effective Hamiltonians developed for ¹²C¹⁶O₂ and ¹³C¹⁶O₂ but significant deviations were evidenced for the ¹⁶O¹³C¹⁸O minor isotopologue. The relative band intensities within each polyad are also discussed on the basis of the effective Hamiltonian model.     

Novel Peak Assignments of in VivoC MRS in Human Brain at 1.5 T

¹³C MRS studies at natural abundance and after intravenous 1-¹³C glucose infusion were performed on a 1.5-T clinical scanner in four subjects. Localization to the occipital cortex was achieved by a surface coil. In natural abundance spectra glucose C_3β,5β, myo-inositol, glutamate C_1,2,5, glutamine C_1,2,5, N-acetyl-aspartate C_1-4,C=O, creatine CH₂, CH₃, and C_C=N, taurine C_2,3, bicarbonate HCO⁻₃ were identified. After glucose infusion ¹³C enrichment of glucose C_1α,1β, glutamate C_1-4, glutamine C_1-4, aspartate C_2,3, N-acetyl-aspartate C_2,3, lactate C₃, alanine C₃, and HCO⁻₃ were observed. The observation of ¹³C enrichment of resonances resonating at >150 ppm is an extension of previously published studies and will provide a more precise determination of metabolic rates and substrate decarboxylation in human brain.     

Line Shift Investigations for Different Isotopomers of Carbon Monoxide

Line shift coefficients for five lines of five different isotopomers in the fundamental band of CO in the spectral region near 2058 cm⁻¹were measured using a three channel lead salt diode laser spectrometer. The study includes the linesP(3) of¹³C¹⁷O,R(3) of¹³C¹⁸O,P(9) of¹²C¹⁸O,P(10) of¹³C¹⁶O, andP(21) of¹²C¹⁶O, and covers collisions with N₂, O₂, H₂, D₂, He, Ne, Ar, Kr, and Xe. Line shifts of the isotopomers¹³C¹⁶O,¹²C¹⁸O,¹³C¹⁸O, and¹³C¹⁷O were determined for the first time. Within the experimental uncertainty no significant dependence of the shift effect on the isotopomer was found. TheR-branch line under study shows a smaller line shift coefficient than aP-branch line with a similar rotational quantum number. With increasing mass of the noble gas perturber the absolute size of the shift coefficient increases. Moreover self- and nitrogen-broadening coefficients for the isotopomer lines were determined. Compared to previous measurements no significant deviations between different isotopomers were observed.     

Depth profiling of cells and tissues by using C60 and SF5 as sputter ions

In the present study, SF₅⁺ and C₆₀⁺ were used as primary ions for sputtering and Bi₃⁺ was used as primary ions for analysis. The depth profiling procedure was utilized to make 3D images of the chemistry of single cultured cells and tissue samples of intact intestinal epithelium.The results show sputtering of organic material from cells and tissue with both SF₅⁺ and C₆₀⁺ sources. Cholesterol fragments were found in the superficial layers when sputtering with C₆₀⁺. Spectra were collected revealing the change in yield along the z-axis of the sample. 3D images of the localization of Na, K, phosphocholine and cholesterol were constructed with both ion sources for single cell cultures and the mouse intestine.Cryostate sections of mouse intestine were analysed in 2D and the results were compared with the 3D image of the intestine. The localization of cholesterol and phosphocholine was found to be similar in cryostate sections analysed in two dimensions and the sputtered, freeze-dried intestine analysed in 3D. The comparison of 2D and 3D images suggest that the phosphocholine signal faded with C₆₀⁺ sputtering. In conclusion, both C₆₀⁺ and SF₅⁺ can be used as primary ion sources for sputtering of organic material from cells and tissues. Consecutive analysis with a Bi₃⁺ source can be used to obtain image stacks that could be used for reconstruction of 3D images.     

Fourier transform microwave spectroscopy of isotopically substituted diacetylenes: rs-structure, quadrupole coupling, and anisotropic nuclear spin-spin interaction

Monodeuterated diacetylene (HCCCCD) and its ¹³C-substituted species H¹³CCCCD, HC¹³CCCD, HCC¹³CCD, and HCCC¹³CD were investigated by Fourier transform microwave spectroscopy. The D nuclear quadrupole splittings were almost completely resolved. For H¹³CCCCD hyperfine splittings caused by the anisotropic nuclear spin-spin interaction between the H and ¹³C nuclei were also observed. The analysis yielded rotational constants, centrifugal distortion constants, and the constants for the nuclear quadrupole coupling and anisotropic nuclear spin-spin interaction. The substitution structure of HCCCCD was calculated as follows: r_s(C-H) = 1.056054(39) Å, r_s(CC) = 1.208631(4) Å, r_s(C-C) = 1.374117(6) Å, r_s(CC) = 1.208116(4) Å, and r_s(C-D) = 1.056231(17) Å, in the order of the arrangement of the bonds. A rough estimate of the equilibrium structure is also presented. The eQq constant for the deuterium nucleus is 0.2061(4) MHz. The anisotropic ¹³C-H spin-spin interaction constant was experimentally determined for the first time as b = −29.2(15) kHz, which is defined as the coefficient of (3I_2zI_3z − I₂ · I₃), where I₂ and I₃ denote the H and ¹³C nuclear spins, respectively, and I_2z and I_3z their components along the molecular axis. The observed b constant is not accounted for by the direct magnetic dipole-dipole interaction only, suggesting a significant contribution from indirect anisotropic interaction.     

Theoretical investigations of the local structure distortion and the spin Hamiltonian parameters of Cr ions at tetragonal charge-compensation defect CrF5O site in Cr: KMgF3 crystals

The local structure distortion and the spin Hamiltonian (SH) parameters, including the zero-field splitting (ZFS) parameter D and the Zeeman g-factors g_‖ and g_⊥, are theoretically investigated by means of complete diagonalization method (CDM) and the microscopic spin Hamiltonian theory for tetragonal charge compensation CrF₅O defect center in Cr³⁺:KMgF₃ crystals. The superposition model (SPM) calculations are carried out to provide the crystal field (CF) parameters. This investigation reveals that the replacement of O²⁻ for F⁻ and its induced lattice relaxation Δ₁(O²⁻) combined with an inward relaxation of the nearest five fluorine Δ₂(F⁻) give rise to a strong tetragonal crystal field, which in turn results in the large ZFS and large anisotropic g-factor Δg. The experimental SH parameters D and Δg can be reproduced well by assuming that O²⁻ moves towards the central ion Cr³⁺ by Δ₁(O²⁻)=0.172R₀ and the five F⁻ ions towards the central ion Cr³⁺ by Δ₂(F⁻)=0.022R₀. Our approach takes into account the spin-orbit (SO) interaction as well as the spin-spin (SS), spin-other-orbit (SOO), and orbit-orbit (OO) interactions omitted in previous studies. This shows that although the SO interaction is the most important one, the contributions to the SH parameters from other three magnetic interactions are appreciable and should not be omitted, especially for the ZFS parameter D.     

Primary ion fluence dependence in time-of-flight SIMS of self-assembled monolayer of alkyl thiol molecules on Au(1 1 1)—Discussion of static limit

The nondestructive nature of static secondary ion mass spectrometry (SIMS) in the context of studies of self-assembled monolayers (SAMs) of organic molecules has been examined by measuring the primary ion fluence dependence of secondary ion signals with two well-known SAMs, C₁₈H₃₇SH on Au(1 1 1) and C₁₈H₃₇PO₃H₂ on freshly cleaved mica. This SIMS analysis is challenging because the bonding nature is delicate and the areal molecular density is less than 10¹⁵ cm⁻². In SIMS, it is prevalently assumed that if the primary ion fluence is confined to not more than 1 × 10¹² cm⁻², all secondary ion signals should not change by more than 10% and the practically defined static condition is satisfied. Our results from time-of-flight SIMS with the common primary ions of Bi₃⁺, Bi⁺ and Ar⁺, indicate that this prevalent static assumption fails for both model SAMs. The SIMS results from the phosphyl case, which have been recently published, consistently display the evidence of bombardment-induced damage. In comparison, the thiol case presented here shows much more complex primary ion fluence dependence of SIMS signals. It is therefore concluded that practical static analysis should use primary ion fluence not more than 1 × 10¹¹ cm⁻² or should simply record and report the effects of primary ion fluence.     

Ethylene adsorption on the Pt-Cu bimetallic catalysts. Density functional theory cluster study

The adsorption of ethylene on Cu₁₂Pt₂ clusters has been studied within the density functional theory (DFT) approach to understand the high ethylene selectivity of Cu-rich Pt-Cu catalyst particles in the reaction of hydrogen-assisted 1,2-dichloroethane dechlorination. The structural parameters for Cu₁₂Pt₂ clusters with D_4h, D_2d, and C_3v symmetry have been calculated. The relative stability of the isomeric Cu₁₂Pt₂ clusters follows the order: C_3v > D_2d > D_4h. Each isomer has an active site for ethylene adsorption that consists of a single Pt atom surrounded by Cu atoms. The interaction of ethylene with the active site yields a π-C₂H₄ adsorption complex. The strongest π-C₂H₄ complex forms with the cluster of C_3v symmetry; the bonding energy, ΔE_π(C₂H₄), is −15.6 kcal mol⁻¹. The bonding energies for the π-C₂H₄ complex with Cu₁₄ and Pt₁₄ clusters are −6.5 and −18.8 kcal mol⁻¹, respectively.The addition of Pt to Cu modifies the valence spd-band of the cluster as compared to a Cu₁₄ cluster. The DOS near the Fermi level increases when C₂H₄ adsorbs on the Cu₁₂Pt₂ cluster. As well, the center of the d-band shifts toward lower binding energies. Ethylene adsorption also induces a number of states below the d-band. These states correspond to those of gas-phase C₂H₄.The vibrational frequencies of C₂H₄ adsorbed on the clusters of D_4h and C_3v symmetry have been calculated. The phonon vibrations occur below 250 cm⁻¹. The intense bands around 200 cm⁻¹ are attributed to stretching vibrations of the Pt-Cu bonds normal to the cluster surface. The stretching vibrations of the Pt-C bonds depend on the local structure of the active site: ν_s(Pt-C) = 268 cm⁻¹ and ν_as(Pt-C) = 357 cm⁻¹ for the cluster of the D_4h symmetry; ν_s(Pt-C) = 335 cm⁻¹ and ν_as(Pt-C) = 397 cm⁻¹ for the cluster of the C_3v symmetry. Bands in the range of 800-3100 cm⁻¹ are attributed to vibrations of the adsorbed C₂H₄ molecule. The signature frequencies of the π-C₂H₄ adsorption complex are the δ_s(CH₂) deformation vibration at ∼1200 cm⁻¹ and the ν(C-C) stretching vibration at ∼1500 cm⁻¹. These vibration are absent for di-σ-C₂H₄ adsorption complexes.     

Energy distributions of atomic and molecular ions sputtered by C60 projectiles

In the process of investigating the interaction of fullerene projectiles with adsorbed organic layers, we measured the kinetic energy distributions (KEDs) of fragment and parent ions sputtered from an overlayer of polystyrene (PS) oligomers cast on silver under 15 keV C₆₀⁺ bombardment. These measurements have been conducted using our TRIFT™ spectrometer, recently equipped with the C₆₀⁺ source developed by Ionoptika, Ltd. For atomic ions, the intensity corresponding to the high energy tail decreases in the following order: C⁺(E^−0.4) > H⁺(E^−1.5) > Ag⁺(E^−3.5). In particular, the distribution of Ag⁺ is not broader than those of Ag₂⁺ and Ag₃⁺ clusters, in sharp contrast with 15 keV Ga⁺ bombardment. On the other hand, molecular ions (fragments and parent-like species) exhibit a significantly wider distribution using C₆₀⁺ instead of Ga⁺ as primary ions. For instance, the KED of Ag-cationized PS oligomers resembles that of Ag⁺ and Ag_n⁺ clusters. A specific feature of fullerene projectiles is that they induce the direct desorption of positively charged oligomers, without the need of a cationizing metal atom. The energy spectrum of these PS⁺ ions is significantly narrower then that of Ag-cationized oligomers. For characteristic fragments of PS, such as C₇H₇⁺ and C₁₅H₁₃⁺ and polycyclic fragments, such as C₉H₇⁺ and C₁₄H₁₀⁺, the high energy decay is steep (E⁻⁴ − E⁻⁸). In addition, reorganized ions generally show more pronounced high energy tails than characteristic ions, similar to the case of monoatomic ion bombardment. This observation is consistent with the higher excitation energy needed for their formation. Finally, the fraction of hydrocarbon ions formed in the gas phase via unimolecular dissociation of larger species is slightly larger with gallium than with fullerene projectiles.     

Determination of the low energy values of CH4 transitions in the 2ν3 region near 1.66 μm from absorption spectra at 296 and 81 K

The high resolution absorption spectra of ¹³CH₄ were recorded at 81 K by differential absorption spectroscopy using a cryogenic cell and a series of distributed feed back (DFB) diode lasers and at room temperature by Fourier transform spectroscopy. The investigated spectral region corresponds to the high energy part of the ¹³CH₄ tetradecad dominated by the 2ν₃ overtone near 5988 cm⁻¹. Empirical line lists were constructed containing, respectively, 1629 ¹³CH₄ transitions detected at 81 K (5852-6124 cm⁻¹) and 3481 features (including 85 lines of ¹²CH₄) measured at room temperature (5850-6150 cm⁻¹); the smallest measured intensities are about 3 × 10⁻²⁶ and 4 × 10⁻²⁵ cm/molecule at 81 and 296 K, respectively. The lower state energy values were derived for 1196 ¹³CH₄ transitions from the variation of the line intensities between 81 and 296 K. These transitions represent 99.2% and 84.6% of the total absorbance in the region, at 81 and 296 K, respectively. Over 400 additional weak features were measured at 81 K and could not be matched to lines observed at room temperature. The quality of the resulting empirical low energy values is demonstrated by the excellent agreement with the already-assigned transitions and the clear propensity of the empirical low J values to be close to integers. The two line lists at 81 and at 296 K provided as Supplementary material will enable future theoretical analyses of the upper ¹³CH₄ tetradecad.     

Studies of the electrochemical reduction processes of Bi, HTeO2 and their mixtures

The reduction process of Bi³⁺, HTeO₂⁺ and their mixtures on Au electrode surface was studied by cyclic voltammetry, linear sweep voltammetry, electrochemical impedance spectroscopy and chronoamperometry. XRD and EDS methods were also used to measure the reductive products prepared under different potentials and provide the evidences of the reactions. The results indicate that the reduction of HTeO₂⁺ occurs at more positive potential than that of Bi³⁺, but its reduction rate is slower and adsorption phenomenon exists during its reduction process. Bi₂Te₃ compound can be obtained potentiostatically at a proper potential in all the mixed solutions with concentration ratio CHTe+O₂/CBi3+ in our research range (0.1-10). But pure Bi₂Te₃ compound can only be obtained at 42 mV in the solution with concentration ratio CHTe+O₂/CBi3+ equaling to 1. And the formation of Bi₂Te₃ compound is an inductive co-depositing process: (1) HTeO₂⁺ + 4e⁻ + 3H⁺ → Te⁰ + 2H₂O, (2) 3Te⁰ + 2Bi³⁺ + 6e⁻ → Bi₂Te₃.