Fundamental Band Research Articles

Ro-vibrational spectral features and pressure broadening dynamics of dideutero-methane (12CH2D2) in the ν9(B2) fundamental band

Dideutero-methane 12CH2D2 is unique among all the methane isotopomers because of its asymmetric-top nature. Here, we first report the fine ro-vibrational gas-phase spectra of 12CH2D2 isotopomer in the a-type ν9 (B2-symmetry) fundamental band near 7.8 µm using ultra-sensitive cavity ring-down spectroscopy (CRDS) instrument in the mid-infrared spectral region. We utilized Gaussian 16 to calculate the relevant spectroscopic parameters of 12CH2D2 and subsequently performed the PGOPHER simulation for precise assignments of the fine ro-vibrational lines of 12CH2D2. Further, we conducted the pressure broadening dynamics of 12CH2D2 isotopomer with various foreign gases and accurately determined the pressure broadening coefficients, γi in cm−1 atm−1 [i = He, Ar, N2, Hydrogen mixture(H2 + N2) and zero air] of various transition lines of 12CH2D2.

High-resolution infrared spectroscopy of supersonically cooled singlet carbenes: Bromomethylene (HCBr) in the CH stretch region.

First high-resolution spectra of cold (∼35K) singlet bromomethylene HCBr in the CH stretching (v1) region from 2770 to 2850cm-1 are reported using near quantum shot-noise limited laser absorption methods in a slit jet supersonic discharge expansion source. Three rovibrational bands are identified at high S/N (20:1-40:1) and rotationally assigned to (i) the CH stretch fundamental (v1) band X̃1,0,0←X̃0,0,0 and (ii) vibrational hot bands [X̃(1,1,0)←X̃(0,1,0) and X̃(1,0,1)←X̃(0,0,1)] arising from vibrationally excited HCBr populated in the discharge with single quanta in either the H-C-Br bend (v2) or C-Br stretch (v3) modes. Precision rotational constants are reported for a total of six states, with an experimentally determined CH stretch vibrational frequency (2799.38cm-1) in good agreement with previous low-resolution fluorescence studies [M. Deselnicu et al., J. Chem. Phys. 124(13), 134302 (2006)]. Detailed analysis of the fundamental v1 band highlights the presence of perturbations in the X̃1,0,0 level, which we tentatively attribute to arise from the nearby triplet state ã(0,0,1) through spin-orbit interaction or the multiple quanta X̃0,2,1 singlet state via c-type Coriolis coupling. Reduced-Doppler resolution (60MHz) in the slit-jet IR spectrometer permits for clear observation of a nuclear spin hyperfine structure, with experimental line shapes well reproduced by nuclear quadrupole/spin-rotation coupling constants from microwave studies [C. Duan et al., J. Mol. Spectrosc. 220(1), 113-121 (2003)]. Finally, the a-type to b-type transition intensity ratio for the fundamental CH stretch band is notably larger than that predicted by using a bond-dipole model, which from high level ab initio quantum calculations [CCSD(T)/PVQZ] can be attributed to vibrationally induced "charge-sloshing" of electron density along the polar C-Br bond.

Features of determining the optical bandgap of amorphous nanosized composite TiO2:Ag films

The study results of optical properties of amorphous nanosized TiO2:Ag composite films with the structure of an amorphous TiO2 matrix with inclusions of isolated Ag nanoparticles are presented. The TiO2:Ag films were obtained by ion-plasma high-frequency magnetron co-sputtering of a polycrystalline TiO2 and Ag target. The films were 40–50 nm thick, and the maximum silver concentration reached 9.0 at.%. The fundamental absorption band edge was analyzed for different possible absorption laws. It is shown that, in TiO2 and TiO2:Ag films, the edge of the fundamental absorption band is formed mainly due to indirect allowed optical transitions (the quadratic absorption law), and this absorption law does not change with increasing silver concentration. The optical bandgap in TiO2:Ag films depends on the Ag concentration and is determined by the degree of order in the amorphous matrix.

Influence of calcination temperature on physical and optical properties of nickel chromite nanoparticles

Nickel chromite nanoparticles were prepared by sol-gel auto combustion method followed by calcination at different temperatures, 700, 900, 1100 and 1300oC for 8h. The prepared nanoparticles were characterized by XRD, SEM, EDS, FTIR and UV-Vis spectroscopy. From the XRD patterns, the Miller indices (hkl) were identified for all the prominent peaks for all the samples, it was clear that the compound crystallized according to spinel structure with a space group of Fd3m. SEM images showed non-uniform agglomerated fragments having a lot of voids and pores. UsingScherrer method, the crystallite size was calculated and found gradually increasing trend with the calcination temperature from 13.73 to 22.33 nm, where as the average grain size was increased from 140.00 to 163.46 nm with calcination temperature. FTIR spectra showed six fundamental absorption bands in the range 500 to 3470 cm-1, whereas the two absorption bands in the range 500-625 cm-1 confirmed the bonding vibrations of metal-oxygen bonds situated at octahedral and tetrahedral sites. UV-Vis spectroscopy was carried out in the wavelength range 200-800 nm and the optical band gap (Eg) was observed in the range 4.2129-4.3115 eV.

Mixed magnetic behavior in gadolinium and ruthenium co-doped nickel oxide nanoparticles

Pure and different concentrations from (Gd, Ru) co-doped NiO nanoparticles, capped with Polyvinylpyrrolidone (PVP), were fabricated by the co-precipitation method. The nanoparticles were characterized by different techniques. The Rietveld refinements of x-ray Diffraction (XRD) patterns confirmed the formation of the pure face-centered-cubic NiO phase. The x-ray Photo-induced Spectroscopy (XPS) assured the trivalent oxidation state of the doped ions Gd3+ and Ru3+ and unveiled the multiple oxidation states of nickel ions (Ni2+ and Ni3+), emerging from the vacancies in the samples. The Transmission Electron Microscope (TEM) images showed the pseudospherical morphology of the samples and the Energy Dispersive x-ray permitted the quantitative analysis of the presented elements and their homogeneous distribution. The Raman and Fourier Transform Infra-Red (FTIR) spectra depicted the fundamental vibrational bands of NiO nanoparticles, confirming their purity. The UV-visible spectroscopy enabled the absorption measurements and the energy gap calculations. The co-dopants increased the energy bandgap of NiO nanoparticles from 3.15 eV for pure NiO to 3.62 eV with the highest concentration of the co-dopants (x = 0.02) The photoluminescence (PL) spectra gave insights into the possible defects present in the samples, such as nickel vacancies, single and double oxygen vacancies, and oxygen interstitials. The Vibrating Sample Magnetometer (VSM) studied the room temperature M-H loops of the co-doped samples. A combination of ferromagnetic, antiferromagnetic, and paramagnetic contributions was noticed and treated according to the law of approach to saturation and bound magnetic polaron (BMP) model. The magnetic parameters, such as the saturation magnetization, exchange and anisotropy field, and the BMP concentration were extracted from the fitted models and discussed in terms of the co-dopants’ concentration. The co-doped samples showed a softer magnetic behavior, which is recommended for data storage applications.

Solution-based synthesis of wafer-scale epitaxial BiVO4 thin films exhibiting high structural and optoelectronic quality.

We demonstrate a facile approach to solution-based synthesis of wafer-scale epitaxial bismuth vanadate (BiVO4) thin films by spin-coating on yttria-stabilized zirconia. Epitaxial growth proceeds via solid-state transformation of initially formed polycrystalline films, driven by interface energy minimization. The (010)-oriented BiVO4 films are smooth and compact, possessing remarkably high structural quality across complete 2′′ wafers. Optical absorption is characterized by a sharp onset with a low sub-band gap response, confirming that the structural order of the films results in correspondingly high optoelectronic quality. This combination of structural and optoelectronic quality enables measurements that reveal a strong optical anisotropy of BiVO4, which leads to significantly increased in-plane optical constants near the fundamental band edge that are of particular importance for maximizing light harvesting in semiconductor photoanodes. Temperature-dependent transport measurements confirm a thermally activated hopping barrier of ∼570 meV, consistent with small electron polaron conduction. This simple approach for synthesis of high-quality epitaxial BiVO4, without the need for complex deposition equipment, enables a broadly accessible materials base to accelerate research aimed at understanding and optimizing photoelectrochemical energy conversion mechanisms.

First-principles study of SrSnO<sub>3</sub> as transparent conductive oxide

As a wide band gap semiconductor with perovskite structure, SnSnO<sub>3</sub> is regarded as a promising candidate of transparent conductive oxides due to its superior properties like high transparency, non-toxicity and low price. In this work, the electronic structure of SrSnO<sub>3</sub> is obtained through first-principles calculations based on HSE06 hybrid functional. Especially, we investigate the defect formation energy and transition levels of the intrinsic and external defects in SrSnO<sub>3</sub>. The intrinsic defects including the anti-site defects (Sr<sub>Sn</sub> and Sn<sub>Sr</sub>), the vacancy defects (V<sub>Sr</sub>, V<sub>Sn</sub>, and V<sub>O</sub>), and the interstitial defects (Sr<sub>i</sub>, Sn<sub>i</sub> and O<sub>i</sub>) are considered while the external doping defects are taken into account, including the substitution of Li, Na, K, Al, Ga, In for Sr site, Al, Ga, In, P, As, Sb for Sn site, and N, P at O site. Subsequently, the suitable doping elements and the corresponding experimental preparation environments are pointed out. Furthermore, we discuss the mechanism of its conductance according to the energy positions of the band edges. Our calculation results demonstrate that SrSnO<sub>3</sub> is an indirect-type semiconductor with a fundamental band gap of 3.55 eV and an optical band gap of 4.10 eV and then has a good visible light transmittance. Its valence band maximum (VBM) comes from O-2p state while its conduction band minimum (CBM) mainly originates from Sn-5s state. In consistent with the delocalized Sn-5s state at CBM, the electron effective mass is light and isotropic, which is beneficial to n-type conductance. The n-type intrinsic defects Sn<sub>Sr</sub> and V<sub>o</sub> have lower defect formation energy than the p-type intrinsic defects under O-poor condition while the n-type and p-type defects with low defect formation energy are almost equal under O-rich condition. Moreover, the transition levels of Sn<sub>Sr</sub> and V<sub>O</sub> are both deep. Therefore, SrSnO<sub>3</sub> cannot have a good conductance without external doping. Our calculations also demonstrate that it is hard to produce an efficient p-type external doping due to the compensation effect by V<sub>O</sub>. On the other hand, substitution of As or Sb for Sn site can result in an effective n-type external doping due to their low defect formation energy and shallow transition levels. According to the low energy positions of VBM (–7.5 eV) and CBM (–4.0 eV) of SrSnO<sub>3</sub>, we explain the reason why it is easy to realize an n-type conductance but hard to produce a high-performance p-type conductance, which follows the doping rules for wide band gap semiconductors. Finally, Sb-doped SrSnO<sub>3</sub> is proposed as a promising candidate for n-type transparent conductive materials.

Retinal Vibrations in Bacteriorhodopsin are Mechanically Harmonic but Electrically Anharmonic: Evidence From Overtone and Combination Bands.

Fundamental vibrations of the chromophore in the membrane protein bacteriorhodopsin (BR), a protonated Schiff base retinal, have been studied for decades, both by resonance Raman and by infrared (IR) difference spectroscopy. Such studies started comparing vibrational changes between the initial BR state (all-trans retinal) and the K intermediate (13-cis retinal), being later extended to the rest of intermediates. They contributed to our understanding of the proton-pumping mechanism of BR by exploiting the sensitivity of fundamental vibrational transitions of the retinal to its conformation. Here, we report on new bands in the 2,500 to 1,800 cm−1 region of the K-BR difference FT-IR spectrum. We show that the bands between 2,500 and 2,300 cm−1 originate from overtone and combination transitions from C-C stretches of the retinal. We assigned bands below 2,300 cm−1 to the combination of retinal C-C stretches with methyl rocks and with hydrogen-out-of-plane vibrations. Remarkably, experimental C-C overtone bands appeared at roughly twice the wavenumber of their fundamentals, with anharmonic mechanical constants ≤3.5 cm−1, and in some cases of ∼1 cm−1. Comparison of combination and fundamental bands indicates that most of the mechanical coupling constants are also very small. Despite the mechanical quasi-harmonicity of the C-C stretches, the area of their overtone bands was only ∼50 to ∼100 times smaller than of their fundamental bands. We concluded that electrical anharmonicity, the second mechanism giving intensity to overtone bands, must be particularly high for the retinal C-C stretches. We corroborated the assignments of negative bands in the K-BR difference FT-IR spectrum by ab initio anharmonic vibrational calculations of all-trans retinal in BR using a quantum-mechanics/molecular mechanics approach, reproducing reasonably well the small experimental anharmonic and coupling mechanical constants. Yet, and in spite accounting for both mechanical and electrical anharmonicities, the intensity of overtone C-C transitions was underestimated by a factor of 4–20, indicating room for improvement in state-of-the-art anharmonic vibrational calculations. The relatively intense overtone and combination bands of the retinal might open the possibility to detect retinal conformational changes too subtle to significantly affect fundamental transitions but leaving a footprint in overtone and combination transitions.

Multifunctional compact dual band repetitively pulsed slab RF discharge CO laser with average output power up to 40 W

A new repetitively pulsed cryogenically cooled slab RF discharge CO laser running in both fundamental and first-overtone bands without its active medium forced replacement with average output power three times as much as that of previous models was developed. Compared to our previous installations, the output power was increased due to using gold-coated copper electrodes of ∼ 1.5 times larger surface area. The fundamental band free-running lasing was obtained within the spectral range of 5.06–5.92 μm with average output up to ∼ 40 W. Under Q-switching the laser operated in the spectral range of 4.95–7.0 μm with pulsed peak power up to 4.5 kW. The first-overtone band lasing was observed in the spectral range of 2.6–3.05 μm with maximum average power of ∼ 6 W.

Nonequilibrium Vibrational, Rotational, and Translational Thermometry via Megahertz Laser Absorption of CO

A mid-infrared laser absorption strategy for simultaneously measuring translational, rotational, and vibrational temperatures of carbon monoxide (CO) at high speeds was developed for application to high-temperature nonequilibrium environments relevant to Mars atmosphere entry. Rapid-tuning scanned wavelength techniques were used to spectrally resolve the R(0,66), P(0,31), P(2,20), and P(3,14) lines of the CO fundamental vibrational bands at a rate of 1 MHz to infer multiple temperatures of CO behind incident and reflected shock waves in a shock tube. A distributed feedback quantum cascade laser was used to probe the P-branch transitions near and an external cavity quantum cascade laser was used to probe the R-branch transition near , both using bias-tee circuitry. The sensing method is shown to resolve each targeted transition with temporal and spectral resolution sufficient for quantitative multi-temperature measurements over a wide range of temperatures and pressures (2100–5500 K, 0.03–1.02 atm), including behind incident shock waves traveling up to 3.3 km/s. Measured temperature results were compared to equilibrium and nonequilibrium simulations.

N2O–Ar and N2O–Kr: Intermolecular vibrations of N2O–Kr and symmetry breaking of the N2O bending mode in the presence of a rare gas

Rotationally-resolved infrared spectra of N2O–Ar and N2O–Kr are studied in the region of the N2O ν1 vibration (≈2224 cm−1) using a tunable Quantum Cascade laser source to probe a pulsed supersonic jet. The N2O–Kr ν1 fundamental band is re-analyzed, together with previous ν3 band data, using a unified scheme to fit the (small) observed Kr isotope splittings. This scheme is then transferred to analyze the bending combination band of N2O–Kr near 2257 cm−1 where isotope effects are much larger due to stretch-bend interactions. As a result, N2O–Kr intermolecular bend (33.29 cm−1) and stretch (34.48 cm−1) frequencies are directly determined for the first time. Weak spectra are detected for both N2O–Ar and –Kr corresponding to the (ν1, ν2l2, ν3) = (1110) ← (0110) hot band of N2O. Their analysis yields the magnitude of the splitting of the N2O ν2 bending mode into in-plane and out-of-plane components. These splittings are found to be significantly smaller than those observed in the analogous CO2-containing dimers.

INFLUENCE OF THE COMPOSITION OF THE RADIO-FREQUENCY SPUTTERING ATMOSPHERE ON THE DENSITY OF STATES AND INTERBAND LIGHT ABSORPTION IN THIN Y2O3 FILMS

The long-wavelength edge of the fundamental absorption band of thin Y2O3 films obtained by radiofrequency ion-plasma sputtering is investigated. The edge of interband absorption after annealing of the films in an atmosphere of argon, oxygen, or a mixture of these gases is shown to be approximated well by the
 Urbach empirical rule. Diffractograms of the obtained films were studied and a model of a heavily doped or defective semiconductor in the quasi-classical approximation was used to analyze the experimental results. This model allows determining the radius of the basic electronic state, the screening radius, and the rootmean-square potential depending on the sputtering atmosphere.

Development of an infrared laser absorption sensor for non-intrusive gas temperature measurements

Energetic materials have extremely high volumetric and specific energy densities, making them attractive and important in combustion systems. To improve their combustion performance, reliable temperature acquirement method is highly demanded. A laser sensor was developed for in situ and quantitative measurements of gas temperature. Scanned-wavelength direct absorption spectroscopy was used for line-of-sight temperature measurements. Multiple H2O absorption features in the near-infrared combination band (v1+v3) and mid-infrared fundamental band (v3) were selected to establish four absorption line pairs with good temperature sensitivity. Three infrared distributed feedback lasers (DFB) were used to cover the selected absorption lines. The accuracy and uncertainty of the sensor were first numerically evaluated in a wide temperature range of 1000–3000 ​K under different Gaussian white noise levels (5–20%). A free-space optical setup was established to experimentally evaluate the sensor performance by measuring benchmark laminar premixed flames, which were compared with additional thermocouple measurements, chemical kinetic modeling and computational fluid dynamics simulations. The good performance of the current sensor indicates the potential of being used in non-intrusive, in-situ and quantitative diagnostics of the energetic materials combustion.

Line mixing study on the fundamental rovibrational band of nitric oxide near 5.3 [formula omitted

In this work, we report quantitative absorbance measurements of nitric oxide (NO) diluted in nitrogen between 1700 to 2000 cm−1 and present three line mixing modeling approaches for the measured spectra. Static cell measurements were taken using a narrow-linewidth, external-cavity quantum-cascade laser at temperatures of 293 K and 802 K and pressures of 20–34 atm. The measured results exhibit considerable deviations from the spectra simulated by a superposition of Lorentzian line profiles due to significant line mixing coupling effects at high-number-density conditions. Our previous work demonstrated a line mixing model based on relaxation matrix theory and the Modified Exponential Gap (MEG) law for the NO R-branch. With expanded access to the P- and Q-branches, the measured data indicated significant line mixing effects between lines of different branches in addition to those within the same branch. An empirical two-scaling-factor inter-branch MEG model is presented that delivers strong agreement across the measured spectra, with residuals less than 2% for the spectrum at 293 K and 34 atm. In addition, the Energy Corrected Sudden (ECS) scaling law is shown to produce reasonable agreement across the measured spectra, excluding the Q-branch. In the Q-branch peak, the ECS model overpredicts the measured data by about 7%. The different line mixing models presented and discussed in this work will improve NO absorption predictions vital for laser absorption applications in high-number-density gas conditions. Future studies may seek to account for inter-spin-split coupling to further improve the ECS application to NO absorption.

On the Issue of the Origin of Type II Solar Radio Bursts

Abstract Type II solar radio bursts are among the most powerful events in the solar radio emission in the meter wavelength range. It is generally accepted that the agents generating type II radio bursts are magnetohydrodynamic shock waves. But the relationship between the shock waves and the other manifestations of the large-scale disturbances in the solar atmosphere (coronal mass ejections, Morton waves, EUW waves) remains unclear. To clarify a problem, it is important to determine the conditions of generation of type II radio bursts. Here, the model of the radio source is based on the generation of radio emission within the front of the collisionless shock wave where the Buneman instability of plasma waves is developed. In the frame of this model, the Alfvén magnetic Mach number must exceed the critical value, and there is a strict restriction on the perpendicularity of the front. The model allows us to obtain the information about the parameters of the shock waves and the parameters of the medium by the parameters of type II bursts. The estimates, obtained in this paper for several events with the band splitting of the fundamental and harmonic emission bands of the type II bursts, confirm the necessary conditions of the model. In this case the registration of type II radio bursts is an indication of the propagation of shock waves in the solar atmosphere, and the absence of type II radio bursts is not an indication of the absence of shock waves. Such a situation should be taken into account when investigating the relationship between type II radio bursts and other manifestations of solar activity.

Re-investigation of the infrared spectrum of the NCN radical by laser magnetic resonance spectroscopy

The laser magnetic resonance (LMR) spectroscopic technique has been used to reinvestigate the mid-infrared spectrum of the NCN free radical in its Σg-3 ground electronic state. A liquid nitrogen-cooled carbon monoxide (CO) laser was used as a source of strong coherent radiation in the 1442–1484 cm−1 region of the infrared. Vibration-rotation transitions were brought into resonance with the laser frequency using magnetic flux densities up to 1.4 T. Spectra were recorded in both parallel (ΔMJ = 0) and perpendicular (ΔMJ = ±1) polarizations with ten CO laser lines. Over one hundred new absorption lines were observed in the LMR spectra and have been subsequently assigned to transitions in either the 301 fundamental band (near 1466.5 cm−1) or the 211301 hot band (near 1455.6 cm−1) of NCN in the Σg-3 ground state. An improved set of molecular parameters for NCN has been determined from a least-squares fit of all the available data on the infrared spectrum, provided by Fourier transform and LMR spectra. In the wake of an exhaustive analysis of the LMR spectra, several additional lines remain. Although chemical tests indicate these lines do not belong to NCN, it has not proved possible to identify their carrier(s).

Relationship between temperature and road traffic noise under actual conditions of continuous vehicle flow

This paper focuses on studying the influence of temperature on the sound pressure level of tire-road noise emission using continuous environmental noise measurements. In situ noise measurements were performed next to a primary road under free flowing traffic where tire‐road noise emission dominates, while simultaneously monitoring the air and pavement temperature. The broadband results showed a variation in noise level with temperature, with a ratio of −0.058 ± 0.007 dBA/°C for the pavement temperature and −0.161 ± 0.020 dBA/°C for the air temperature. A 1/3 octave band analysis revealed a decrease in sound level with increasing temperature in the fundamental bands of road traffic noise emission, and similar behaviour and values to that observed in the broadband analysis. The physical media in which temperature is measured appears to be important. Several implications may arise from this work in regard to reference standards for noise evaluation, calculation and measurement.

Quantitative and Sensitive Mid-Infrared Frequency Modulation Detection of HCN behind Shock Waves

Despite its key role for the study and modeling of nitrogen chemistry and NOx formation in combustion processes, HCN has only rarely been detected under high-temperature conditions. Here, we demonstrate quantitative detection of HCN behind incident and reflected shock waves using a novel sensitive single-tone mid-infrared frequency modulation (mid-IR-FM) detection scheme. The temperature-dependent pressure broadening of the P(26) line in the fundamental CH stretch vibration band was investigated in the temperature range 670K≤T≤1460K, yielding a pressure broadening coefficient for argon of 2γAr296K=(0.093±0.007)cm−1atm−1 and a temperature exponent of nAr=0.67±0.07. The sensitivity of the detection scheme was characterized by means of an Allan analysis, showing that HCN detection on the ppm mixing ratio level is possible at typical shock wave conditions. In order to demonstrate the capability of mid-IR-FM spectroscopy for future high-temperature reaction kinetic studies, we also report the first successful measurement of a reactive HCN decay profile induced by its reaction with oxygen atoms.

Infrared spectroscopy of radioactive hydrogen chloride H36Cl

We present the first report of optical absorption spectroscopy of H36Cl, a radioactive isotopologue of hydrogen chloride. We used Fourier-transform infrared spectroscopy to determine the line center wavenumbers of the fundamental rovibrational band lines P(10)–R(10) and the first overtone band lines P(1)–R(7) with total uncertainty of less than 0.0018 cm−1 (60 MHz) and 0.007 cm−1 (0.2 GHz), respectively, at 68% confidence level. We also performed a rotational analysis on the bands to determine the related molecular constants. We further compared the linewidths and relative intensities of the lines to those of the stable isotopologues H35Cl and H37Cl. The new spectroscopic information assists in developing optical instrumentation for the detection of H36Cl.

Anharmonic effects on Vibrational circular dichroism and Raman optical activity spectra of medium‐size molecules: Alpha‐pinene and beta‐pinene

AbstractAn analysis of the vibrational circular dichoism (VCD) and Raman optical activity (ROA) of two medium‐sized molecules, alpha‐pinene and beta‐pinene, was performed using the second‐order perturbative PT2 method. We calculated the intensity (I in ) using the differential cross section. We reproduce mid‐IR spectra by generalized vibrational PT2 (GVPT2), where the GVPT2 approach has been applied to calculate both vibrational band wavenumbers and intensities to determine anharmonic effects on the spectral shape, adding combination bands to fundamental transition bands. Furthermore, the comparison with experimental spectra for both the band positions and the intensity pattern, our calculation, was evaluated.