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The Ritz program is a user-interactive software package that simulates and enables the assignment of spectra of asymmetric top molecules, up to high rotational quantum numbers. The set of initial assignments can be extended using generated predictions for line positions. The graphical interface of the program handles wide spectral features corresponding to overlapped lines by fitting the expected number of profiles to the experimental contour. Features of the program allow for the detection and examination of Coriolis interactions. Initially designed to work for methanol and its isotopologues, the program has been modified to assign the spectra of cyanamide, hydrazine, acetaldehyde, and oxetane. An extension of the program, LaseRitz, has been developed for the assignment and prediction of optically pumped far-infrared laser transitions. Our paper presents a description of how the Ritz program works and provides an overview of studies carried-out using this software.

This paper discusses recent approaches to gender-inclusive mentoring and leadership at different stages of one’s professional life. We will discuss life scenarios where mentoring makes a difference, different types of mentoring, how to find a mentor, roles and expectations of mentors and mentees, mentoring events, and challenges in the mentoring process. We will outline the importance of leadership activities in the professional development of young professionals. Traits of good leaders, leadership strategies, and lessons learned from good leadership examples, will be presented. Last, we will discuss different ways of defining and achieving success in professional life and beyond.

Transitions of NH2D and ND2H have been detected in the high resolution spectrum of 14ND3 recorded at unapodized resolution of 0.00096 cm−1 in the region 60–600 cm−1 using the Bruker IFS 125 Fourier transform spectrometer located at the synchrotron far-infrared beamline, Canadian Light Source. In this study we report on the observation and analysis of the spectrum for the ground state of NH2D and ND2H. 2153 rotation and rotation-inversion transitions, with J up to 24, were assigned for NH2D, and 3214 transitions, with J up to 28, for ND2H. The newly assigned transitions, together with those present in the literature, were fitted on the basis of a Watson-type S reduced Hamiltonian using the IIIr and IIIl representations for NH2D and ND2H, respectively. The model Hamiltonian includes terms up to the 10th power of the angular momentum and vibration–rotation interaction terms between the inversion states. Precise and extended sets of spectroscopic effective parameters were derived for both isotopologues as results of least squares weighted fit procedures that reproduce the transition wavenumbers at experimental accuracy.

The a, s inversion levels of v2 = 3 and v2 = v4 = 1 vibration states of 15NH3 are studied from high resolution infrared spectra up to 3200 cm−1. Spectra were recorded from 60 to 2000 cm−1 using the Bruker IFS 125 interferometer located at the Canadian Light Source and from 1900 to 3200 cm−1 using the Bomem DA 008 in Bologna. Transitions in 3ν2 and ν2+ν4, in the 3ν2 ← ν2, ν2+ν4 ← ν2, 3ν2 ← 2ν2, ν2+ν4 ← 2ν2, 3ν2 ← ν4, ν2+ν4 ← ν4, and 3ν2 ↔ ν2+ν4 hot bands, and the rotation-inversion transitions in 3ν2 and ν2+ν4 have been observed. 5770 transitions with J max ′ / K max ′ up to 15 have been assigned, including 395 perturbation allowed ones. All transitions were fitted simultaneously on the basis of a rotation-inversion Hamiltonian which includes distortion constants up to 10th power in the angular momentum and all symmetry allowed interaction parameters between and within the a, s inversion levels of v2 = 3 and v2 = v4 = 1. The term values of the lower levels of transitions have been calculated using the parameters recently derived for the ground and v2 = 1, 2 and v4 = 1 states. The data were reproduced at experimental accuracy. The results are compared with those of 14NH3. The experimental transitions are compared with their theoretically predicted values. The list of assignments is supplied as supplementary material. The present results noticeably improve the wavenumber line list in the HITRAN 2016 data base.

Pure CO2 spectra recorded at room temperature and different pressures (0.2–140 Torr) have been analyzed with the help of a fitting routine that takes into account asymmetries arising in the spectral lines due to pressure induced effects such as line mixing. The fitting procedure used in this study allows one to adjust the ro-vibrational constants for the band rather than fitting for individual line parameters. These constrained parameters greatly reduce the measurement uncertainties and allow us to observe the behavior of the weak lines corresponding to high J quantum numbers. We have also calculated line mixing parameters using approximations based on exponential nature of the energy difference between ground and upper vibrational states involved in the ro-vibrational band transitions. The calculated results show good agreement when compared with the experimentally determined parameters.

We report measurement results for line positions, intensities, half-width, and pressure-induced shift coefficients and line mixing coefficients for N2O broadened by air in the ν3 band. The high signal-to-noise ratio spectra have been recorded at high resolution using the McMath–Pierce Fourier transform spectrometer formerly located at the National Solar Observatory on Kitt Peak, Ariz., USA. The spectra were analyzed using a multispectrum nonlinear least-squares curve-fitting technique employing the speed-dependent Voigt profile with a Rosenkranz (weak) line mixing component. The speed dependence parameters were calculated as suggested in the study of Kochanov (J. Quant. Spectrosc. Radiat. Transf. 189, 18 (2017). doi: 10.1016/j.jqsrt.2016.11.007 ). Several comparisons have been performed between the retrieved parameters and previously published results. For |m| ≤ 40, our results for line positions, broadening, and line mixing coefficients agree best with the results of Loos et al. (J. Quant. Spectrosc. Radiat. Transf. 151, 300 (2015). doi: 10.1016/j.jqsrt.2014.10.008 ). Also, we compared the obtained line positions and intensities with the corresponding values in HITRAN2016 and GEISA-2015 databases. No significant or systematic differences were noticed. The precision of our line positions was estimated to be 3 × 10−5 cm−1. The reported line positions, intensities, and air-broadening coefficients are accurate to better than 2%. The accuracy of air-pressure-induced line shifts and line mixing coefficients is better than 5%. The line mixing coefficients and air-broadening coefficients were also calculated using the exponential power gap scaling law, and these calculated values were found to be in good agreement with the experimental results.

We have recently analyzed the broadband millimeter-wave rotational spectrum of chloroform CH35Cl3 in the v3 = v6 = 1 (E symmetry) and v6 = 2 (A1 + E) excited vibrational states . In the present work, we have used the same spectrum (recorded in the 150 - 330 and 360–660 GHz spectral regions) for a rotational analysis of the v2 = 1 and v3 = 2 A1 states of the same molecule, together with a new analysis of the v5=1 (E) fundamental vibration. For the v2 = 1 state (A1, near 677 cm−1), the body of assigned data comprises 392 rotational transitions. The corresponding frequencies were fitted within an isolated-level model, with a standard deviation of 36.4 kHz, and the obtained parameters are in good agreement with the previous IR work. For the v3 = 2 vibrational state (A1, near 734 cm−1), a total of 351 rotational transitions were assigned. Their fit was improved by inclusion of a second-order Coriolis coupling term with the v5 = 1 fundamental level, providing standard deviation of 40.2 kHz. At the same time, the description of the v5 = 1 vibration (E symmetry, 776 cm−1), studied previously with high-resolution as an isolated level, was also improved. The quantitative interpretation of the newly assigned 612 MMW data and the significantly extended set of IR assignments necessitated the introduction of the second-order Coriolis interaction with v3 = 2, but more importantly of an anharmonic interaction with the v6 = 3 (A1 + A2 + E, near 782 cm−1) level. For this latter level more than 200 rotational transitions, together with several series of rovibrational transitions, could finally be assigned and included in the fit.

CO2-broadened line widths and CO2-pressure induced line shifts have been measured for 42 R- and P-branch transitions in the ν1+ν3 band of acetylene at seven temperatures in the range 216–333 K to obtain the temperature dependences of broadening and shift coefficients. The spectra were recorded by a 3-channel tunable diode laser spectrometer, and the traditional Voigt-profile model was employed to retrieve the line parameters with a multispectrum fitting procedure. The line-broadening and line-shifting coefficients as well as their temperature-dependence parameters have been also evaluated theoretically, in the frame of a semi-empirical approach based on analytical Anderson-type expressions and including a few-parameter correction to account for the real curved trajectories. Being validated by comparison with measurements, this approach has been used to compute extensive (0≤J≤70) R- and P-line lists which could be useful for atmospheric/astrophysical applications and spectroscopic databases.

Fourier-transform spectra of room-temperature carbon dioxide compressed to pressures up to 19 atm reported previously are re-analyzed to obtain weak line-mixing parameters and a representation of full line mixing for transitions observed in the P- and Q-branches of the 11101 ← 00001 (Π ← Σ) band centered at 2076.86 cm−1. Similar analyses for the R-branch transitions are prevented by strong Coriolis resonances that nearly completely transfer the intensities of R-branch transitions to the P-branch. The weak line mixing coefficients are retrieved experimentally and are modeled using the Exponential Power Gap scaling law. Another modeling is performed with an Energy-Corrected-Sudden type approach making use of a symmetric relaxation matrix satisfying all basic relations. Comparisons of experimental and calculated parameters with results available in the literature are presented and discussed.

This paper outlines the major updates of the line-shape parameters that were performed for the nitrous oxide (N 2 O) and carbon monoxide (CO) molecules listed in the HITRAN2020 database. We reviewed the collected measurements for the air- and self-broadened N 2 O and CO spectra to determine proper values for the spectroscopic parameters. Careful comparisons of broadening parameters using the Voigt and speed-dependent Voigt line-shape profiles were performed among various published results for both N 2 O and CO. Selected data allowed for developing semi-empirical models, which were used to extrapolate/interpolate existing data to update broadening parameters of all the lines of these molecules in the HITRAN database. In addition to the line broadening parameters (and their temperature dependences), the pressure shift values were revised for N 2 O and CO broadened by air and self for all the bands. The air and self speed-dependence of the broadening parameter for these two molecules were added for every transition as well. Furthermore, we determined the first-order line-mixing parameters using the Exponential Power Gap (EPG) scaling law. These new parameters are now available at HITRAN o n l i n e .

Due to the importance of methane as a trace atmospheric gas and a greenhouse gas, we have carried out a precise line-shape study to obtain the CH 4 –CH 4 and CH 4 –air half-width coefficients, CH 4 –CH 4 and CH 4 –air shift coefficients and off-diagonal relaxation matrix element coefficients for methane transitions in the spectral range known as the “ methane Octad ”. In addition, the associated temperature dependences of these coefficients have been measured in the 4300–4500 cm −1 region of the Octad. The high signal to noise ratio spectra of pure methane and of dilute mixtures of methane in dry air with high resolution have been recorded at temperatures from 148 K to room temperature using the Bruker IFS 125 HR Fourier transform spectrometer (FTS) at the Jet Propulsion Laboratory, Pasadena, California. The analysis of spectra was done using a multispectrum non-linear least-squares curve fitting technique. Theoretical calculations have been performed and the results are compared with the previously published line positions, intensities and with the line parameters available in the GEISA and HITRAN2012 databases.

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This paper offers an overview of multimedia-based teaching tools and teaching methods tested during several introductory physics courses taught to students enrolled in physics, science, and pre-engineering programs at the University of Lethbridge, Lethbridge AB, Canada.

This paper presents a review of some improvements in the status of women in physics in Canada in the past three years as a result of joint efforts by government, academics, industry participants, the Canadian Association of Physicists, granting agencies, and representatives of outreach and science promotion programs.

Fourier transform absorption spectra of the 2–0 band of 12 C 16 O mixed with CO 2 have been recorded at total pressures from 156 to 1212 hPa and at 4 different temperatures between 240 K and 283 K. CO 2 pressure-induced line broadening and line shift coefficients, and the temperature dependence of the former have been measured including line mixing using a multi-spectrum non-linear least squares fitting technique. Different line shape models have been considered to take into account the Dicke narrowing or speed dependence effects. Measured line-shape parameters were compared with theoretical values, calculated for individual temperatures using a semi-empirical method and the Exponential Power Gap (EPG) law.

International audience; We have analyzed 10 room temperature spectra of the fundamental band of CO and CO-air using the Voigt, speed-dependent Voigt, speed-dependent Rautian line shape models. Line positions, intensities, air- and self-broadening coefficients, pressure induced air- and self-shift coefficients, and line-mixing parameters have been retrieved. The CO- and N2-broadened carbon monoxide half width coefficients have been calculated using a potential energy surface based on Tipping-Herman intermolecular interaction potential and taking the electrostatic interactions into account. © Published under licence by IOP Publishing Ltd.

Accurate knowledge of spectral line shape parameters is important for infrared transmission and radiance calculations in the terrestrial atmosphere. In this paper, we report the self- and air-broadened Lorentz half-widths, pressure-induced shifts and line mixing coefficients (via off-diagonal relaxation matrix elements) along with their temperature dependences for methane ν2+ν3 absorption lines in the 4500–4630 cm−1 region of the Octad. For this, we recorded 14 high-resolution, high signal to noise ratio (S/N) spectra of high-purity (99.95% 12C-enriched) samples of pure methane and its dilute mixtures in dry air between 298 K and 148 K. A Bruker IFS 125HR Fourier transform spectrometer (FTS) at the Jet Propulsion Laboratory, Pasadena, California, was used to obtain the experimental data. The absorption cell used for this study was a specially built 20.38 cm long coolable cell installed in its sample compartment. The sample pressures for the pure 12CH4 spectra were 4.5−385 Torr; for the air-broadened spectra the total pressures ranged between 95 and 300 Torr with the methane volume mixing ratios between 0.04 and 0.097. All 14 spectra were fitted simultaneously using an interactive multispectrum nonlinear least-squares curve fitting technique. The results are compared to values reported in the literature.

Two atmospheric trace gases, namely methane and carbon monoxide have been considered in this study. Fourier transform absorption spectra of the 2-0 band of 12C16O mixed with CO2 have been recorded at total pressures from 156 to 1212 hPa and at 4 different temperatures between 240 K and 283 K. CO2 pressure-induced line broadening and line shift coefficients, and the associated temperature dependence have been measured in an multi-spectrum non-linear least squares analysis using Voigt profiles with an asymmetric profile due to line mixing. The measured CO2-broadening and CO2-shift parameters were compared with theoretical values, calculated by collaborators. In addition, the CO2-broadening and shift coefficients have been calculated for individual temperatures using the Exponential Power Gap (EPG) semi-empirical method. We also discuss the retrieved line shape parameters for Methane transitions in the spectral range known as the Methane Octad. We used high resolution spectra of pure methane and of dilute mixtures of methane in dry air, recorded with high signal to noise ratio at temperatures between 148 K and room temperature using the Bruker IFS 125 HR Fourier transform spectrometer (FTS) at the Jet Propulsion Laboratory, Pasadena, California. Theoretical calculations for line parameters have been performed and the results are compared with the previously published values and with the line parameters available in the GEISA2015 [1] and HITRAN2012 [2] databases., SCOPUS: cp.j, info:eu-repo/semantics/published

International audience; Lorentz self- and H2-broadened half-width and pressure-induced shift coefficients, line mixing coefficients as well as line center positions and intensities were obtained using a nonlinear least square fitting technique for 48 (P(24) to R(23)) ro-vibrational transitions belonging to the first overtone (2←0) band of 12C16O at room temperature. All spectra in the 4146 to 4332 cm−1 spectral interval were fitted simultaneously employing four line shape functions: the Voigt, Speed Dependent Voigt, Rautian and Speed Dependent Rautian profiles. The collisional line mixing effect has been observed and investigated as an asymmetry in the analyzed line profiles. A semi-empirical Exponential Power Gap Law method was used to estimate the self- and H2-broadening coefficients and the collisional line mixing parameters. Additionally, a classical approach was applied to calculate the half-width coefficients of transitions in the 2←0 band for carbon monoxide broadened by H2 and for pure CO. The classical approach based on a simple computational method, ensures the molecular motion is correctly characterized in 3 dimensions. The calculations used vibrationally independent intermolecular interaction potentials. The variation of CO half-width coefficients with rotational quantum number J ≤ 24 was computed and compared with measurements. The agreement between the theoretical broadening coefficients is better for pure CO rather than for the CO-H2 system.

The high resolution spectrum of 15NH3 has been recorded at unapodized resolution of 0.00096 cm−1 in the region 60–600 cm−1 using the Bruker IFS 125 Fourier transform spectrometer located at the far-infrared beam-line, Canadian Light Source. We report on the observation and analysis of the rotation-inversion spectrum in the ground, v2=1, 2 and v4=1 states. All the rotation-inversion transitions in the ground state together with the pure inversion transitions present in the literature were fitted simultaneously on the basis of a rotation-inversion Hamiltonian which includes distortion constants up to the 12th power in the angular momentum and the Δk=±3 and Δk=±6 interaction terms. A set of effective parameters was also obtained for the v2=1 state adopting the same theoretical model. For the v2=2 and v4=1 states only a list of observed transitions is reported. The wavenumbers of all the assigned transitions were compared with their theoretically predicted values [S.N. Yurchenko, J. Quant. Spectrosc. Radiat. Transf., 2015, 152, 28]. The present results noticeably improve the wavenumber line list in the HITRAN data base [L. S. Rothman et al. J. Quant. Spectrosc. Radiat. Transf.,2013, 130, 4].

We present a line-shape study of six absorption lines P(21), P(16), P(19), R(16), R(19) and R(21) in the ν1+ν3 band of the acetylene perturbed by nitrogen. The spectra were recorded using a 3-channel diode laser spectrometer. For each transition studied, the N2-broadening, N2-narrowing, N2-pressure induced line shift and N2-line mixing coefficients were retrieved using several line-shape models. Moreover, we compare the N2-narrowing parameter to the dynamical friction parameter. The spectra were recorded over a pressure range from 5 to 250 Torr, and were analyzed using the Voigt, Rautian, Correlated Rautian, Galatry, Rautian–Galatry, Speed Dependent Voigt, Speed Dependent Rautian and Correlated Speed Dependent Rautian line-shape models. Furthermore, we have studied the influence of the type of interaction potential in our analysis for line-shape models that take into account speed dependent effects.

International audience; We report revisited experimentally retrieved and theoretically calculated He-broadened Lorentz half-width coefficients and He- pressure-shift coefficients of 45 carbon monoxide transitions in the 1

15NH3 is the object of extensive investigation due to the central role of ammonia in astronomical sciences and to the complexity of modeling its interacting vibrationally excited states. Of major interest in astrochemistry is the determination of the 14N/15N ratio in space, characterized by unexpected variability among different solar system objects and reservoirs. Recently, the spectroscopic analysis of ground and v2 = 1 a, s states of 15NH3 has been completed at experimental accuracy. Here, the characterization of the a, s inversion symmetry levels of v2 = 1, 2 and v4 = 1 states is presented. New spectra of 15NH3 have been recorded from 325 to 2000 cm−1 at a resolution ranging from 0.00096 cm−1 to 0.003 cm−1, using the Canadian Light Source synchrotron at CLS. 7518 transitions covering nine bands, ν2, 2ν2, ν4, 2ν2 ← ν2, ν4 ← ν2, 2ν2 ↔ ν4 and the inversion-rotation transitions in the excited states, have been fitted simultaneously. The effective Hamiltonian adopted includes all symmetry allowed interactions between and within the studied excited states, according to the most recent results on ammonia. The transitions have been reproduced at experimental accuracy using 185 spectroscopic parameters, determined with high precision. The leading diagonal parameters, Gv, B, C, D’s, compare well with those of 14NH3. The wavenumbers of the assigned transitions are compared with their theoretically predicted values. An improved set of ground state parameters is also derived. These results noticeably improve the wavenumber line list in the high-resolution transmission molecular absorption (HITRAN) database.

The near-infrared (NIR) emission spectrum of H 12 C 15 N was measured in the 6050–6500 cm −1 range at a resolution of 0.044 cm −1 using an emission setup available at the Justus-Liebig Universitat, Giessen, Germany. The rich emission spectrum showing numerous overlapped spectral profiles was analyzed with the spectrum analysis software SyMath running using Mathematica as a platform. This approach allowed us to retrieve the vibrational–rotational constants for 32 bands. Many spectroscopic transitions have been observed for the first time in a lab environment. We quantified four newly observed Coriolis resonances.

Recently, the high radiance of synchrotron sources has been used to enhance FTIR spectrometer performance. However, excessive channel spectra when synchrotron sources are used degrade the quality of retrieved spectral parameters. We have investigated seven different techniques for handling channel spectra. These techniques were used to reduce channel spectra for a test group of seven samples of CO2 mixed with air recorded using the synchrotron source at the Canadian Light Source. The increases in signal to noise ratio (SNR) of spectra handled with each technique were calculated. SNR results showed that transmission spectra, produced using synthetic background spectra with simulated channel spectra, achieved the highest SNR improvement. However, when the spectra groups were fitted using a nonlinear least square fit algorithm, the technique using channel spectra fitting produced the smallest fitting residual. Moreover, the retrieved intensities and air broadening coefficients of 21 spectral lines showed that the spectral fitting technique produced the most accurate values as compared to the HITRAN 2008 database (Rothman et al. J. Quant. Spectrosc. Radiat. Transfer, 110, 533 (2009)). Although the spectral fitting technique was accurate in retrieving spectral line parameters, applying the technique at wider spectral ranges reduced this accuracy.

The spectral line parameters of carbon dioxide have been measured in the laser band I (00011 ← 10001) centred at 10.4 μm. The spectra were recorded at room temperature using the spectroscopic instrumentation at the far-infrared beamline, Canadian Light Source, Saskatoon, Sask. The spectral line intensities, air- and self- broadened Lorentz half widths, and pressure-induced shift coefficients were retrieved for 48 spectral lines using a multispectrum fit technique (Benner et al. J. Quant. Spectrosc. Radiat. Transfer, 53, 705 (1995)). Line parameters were retrieved using the Voigt and speed-dependent Voigt models. The deviations between our results and other results reported in the literature and in the HITRAN08 (Rothman et al. J. Quant. Spectrosc. Radiat. Transfer, 110, 533 (2009)) database were examined and discussed. The effect of errors in fitting channel spectra parameters was examined and found to be mitigated by the inclusion of channels in the multispectral fit.

Analysis of synchrotron FTIR spectra has revealed new assignments for a number of optically pumped far-infrared laser lines from the CH 3 17 OH isotopologue of methanol, with definitive confirmation provided by recent accurate measurements of the laser frequencies. In this Note the lasing energy level systems are discussed, and the spectroscopic evidence for the assignments is presented.

The GEISA database (Gestion et Etude des Informations Spectroscopiques Atmosphériques: Management and Study of Atmospheric Spectroscopic Information) has been developed and maintained by the ARA/ABC(t) group at LMD since 1974. GEISA is constantly evolving, taking into account the best available spectroscopic data. This paper presents the 2015 release of GEISA (GEISA-2015), which updates the last edition of 2011 and celebrates the 40th anniversary of the database. Significant updates and additions have been implemented in the three following independent databases of GEISA. The “line parameters database” contains 52 molecular species (118 isotopologues) and transitions in the spectral range from 10−6 to 35,877.031 cm−1, representing 5,067,351 entries, against 3,794,297 in GEISA-2011. Among the previously existing molecules, 20 molecular species have been updated. A new molecule (SO3) has been added. HDO, isotopologue of H2O, is now identified as an independent molecular species. Seven new isotopologues have been added to the GEISA-2015 database. The “cross section sub-database” has been enriched by the addition of 43 new molecular species in its infrared part, 4 molecules (ethane, propane, acetone, acetonitrile) are also updated; they represent 3% of the update. A new section is added, in the near-infrared spectral region, involving 7 molecular species: CH3CN, CH3I, CH3O2, H2CO, HO2, HONO, NH3. The “microphysical and optical properties of atmospheric aerosols sub-database” has been updated for the first time since 2003. It contains more than 40 species originating from NCAR and 20 from the ARIA archive of Oxford University. As for the previous versions, this new release of GEISA and associated management software facilities are implemented and freely accessible on the AERIS/ESPRI atmospheric chemistry data center website., SCOPUS: ar.j, info:eu-repo/semantics/published

International audience; We report experimental measurements and theoretical calculations for He-broadened Lorentz half-width coefficients andHe- pressure-shift coefficients of 45 carbon monoxide transitions in the 1-0 band. The high-resolution spectra analyzed inthis study were recorded over a range of sample temperatures between 296 and 80 K. The He-broadened line parameters andtheir temperature dependences were retrieved using a multispectrum nonlinear least squares analysis program. A previousanalysis of these spectra used only the Voigt line shape. In the present study four line shape models were compared includingVoigt, speed dependent Voigt, Rautian (to take into account confinement narrowing) and Rautian with speed dependence. Theline mixing coefficients have been calculated using the Exponential Power Gap scaling law. We were unable to retrieve thetemperature dependence of the line mixing coefficients. The current measurements and theoretical results are compared withother published results, where appropriate.

This paper presents the results of a spectroscopic line shape study of self- and nitrogen-broadened 12CH3D transitions in the ν3 and ν5 bands in the Triad region. We combined five pure gas spectra with eighteen spectra of lean mixtures of 12CH3D and nitrogen, all recorded with a Bruker IFS-125 HR Fourier transform spectrometer. The spectra have been analyzed simultaneously using a multispectrum nonlinear least squares fitting technique. N2-broadened line parameters for 184 transitions in the ν3 band and 205 transitions in the ν5 band were measured. In addition, line positions and line intensities were measured for 168 transitions in the ν3 band and 214 transitions in the ν5 band. We have observed 10 instances of weak line mixing corresponding to K″=3 A1 or A2 transitions. Comparisons were made for the N2-broadening coefficients and associated temperature exponents with corresponding values calculated using a semi-classical Robert Bonamy type formalism that involved an inter-molecular potential with terms corresponding to short- and long-range interactions, and exact classical molecular trajectories. The theoretical N2-broadened coefficients are overestimated for high J values, but are in good agreement with the experimental values for small and middle range J values.

N2-broadened line widths and N2-pressure induced line shifts have been measured for transitions in the ν1 + ν3 band of acetylene at seven temperatures in the range 213–333 K to obtain the temperature dependences of broadening and shift coefficients. For the room-temperature spectra the line mixing effects have been also investigated. The Voigt and hard-collision line profile models were used to retrieve the line parameters. All spectra were recorded using a 3-channel tuneable diode laser spectrometer. The line-broadening and line-shifting coefficients as well as their temperature-dependence parameters have been also evaluated theoretically, in the frame of a semi-classical approach based on an exponential representation of the scattering operator, an intermolecular potential composed of electrostatic quadrupole–quadrupole and pairwise atom–atom interactions as well as on exact trajectories driven by an effective isotropic potential.

In this study we have retrieved the self-broadened widths, self-pressure-induced shifts, and Dicke narrowing coefficients for 20 R-branch transitions in the ν1 + ν2 + ν4 + ν5 band of acetylene. The spectra were recorded using a three-channel diode laser spectrometer, a temperature-controlled cell of fixed length and a second, room temperature cell. The soft collision (Galatry) and hard collision (Rautian) profiles with inclusion of line mixing effects were used to retrieve the line parameters. We determined the temperature dependencies for line broadening, shift, and Dicke narrowing coefficients. We performed comparisons between our retrieved line parameters and published line parameters for acetylene transitions.

The vibration–rotation spectra of 13C substituted acetylene, 13C2H2, have been recorded in the region between 60 and 2600 cm−1 at an effective resolution ranging from 0.001 to 0.006 cm−1. Three different instruments were used to collect the experimental data in the extended spectral interval investigated. In total 9529 rotation vibration transitions have been assigned to 101 bands involving the bending states up to v tot = v 4 + v 5 = 4, allowing the characterization of the ground state and of 33 vibrationally excited states. All the bands involving states up to v tot = 3 have been analyzed simultaneously by adopting a model Hamiltonian which takes into account the vibration and rotation l-type resonances. The derived spectroscopic parameters reproduce the transition wavenumbers with a RMS value of the order of the experimental uncertainty. Using the same model, larger discrepancies between observed and calculated values have been obtained for transitions involving states with v tot = 4. These could be sa...

Temperature dependences of pressure-broadened half-width and pressure-induced shift coefficients along with accurate positions and intensities have been determined for transitions in the 2←0 band of 12C16O from analyzing high-resolution and high signal-to-noise spectra recorded with two different Fourier transform spectrometers. A total of 28 spectra, 16 self-broadened and 12 air-broadened, recorded using high-purity (≥99.5% 12C-enriched) CO samples and CO diluted with dry air (research grade) at different temperatures and pressures, were analyzed simultaneously to maximize the accuracy of the retrieved parameters. The sample temperatures ranged from 150 to 298 K and the total pressures varied between 5 and 700 Torr. A multispectrum nonlinear least squares spectrum fitting technique was used to adjust the rovibrational constants (G, B, D, etc.) and intensity parameters (including Herman–Wallis coefficients), rather than determining individual line positions and intensities. Self- and air-broadened Lorentz half-width coefficients, their temperature dependence exponents, self- and air-pressure-induced shift coefficients, their temperature dependences, self- and air- line mixing coefficients, their temperature dependences and speed dependence have been retrieved from the analysis. Speed-dependent line shapes with line mixing employing off-diagonal relaxation matrix element formalism were needed to minimize the fit residuals. This study presents a precise and complete set of spectral line parameters that consistently reproduce the spectrum of carbon monoxide over terrestrial atmospheric conditions.

The far infrared spectrum of HCOOH was recorded at a high resolution (0.0009 cm−1) and long path length (72 m) at the far-infrared beamline, Canadian Light Source. Spectra were recorded in the region 62–300 cm−1, showing transitions from the trans-isomer. Ground state rotational transitions with Ka up to 30, were identified up to 175 cm−1, extending the observation reported in the literature. A total of 3321 transitions were assigned and fitted together with previous (4149) published data. An improved set of rotational parameters was obtained adopting the symmetric top (A) reduction of the rotational Hamiltonian in the Ir representation. The newly measured far infrared transitions allowed the determination of all diagonal and off diagonal 8th order parameters L and of some of the diagonal 10th order parameters P.

Semiclassical calculations of self-broadening and self-induced pressure shift coefficients in the ν 1 + ν 2 + ν 4 + ν 5 band of C2H2 have been performed by considering, in addition to the main electrostatic quadrupole–quadrupole interaction, a simple anisotropic dispersion contribution, leading to results in overall satisfactory agreement with recent measurements [C. Povey, A. Predoi-Cross and D.R. Hurtmans, J. Mol. Spectrosc., 268, 177 (2011)]. In these calculations we have used the mean relative velocity and also considered the Maxwell–Boltzmann distribution of relative velocities. From the theoretical results obtained at different temperatures ranging from 200 to 350 K, we have determined temperature exponents of the broadenings using a simple power law, as well as coefficients of empirical linear and quadratic temperature dependences for the line shifts. These theoretical exponents and linear coefficients, derived from averaging over the distribution of velocities and from the mean thermal velocity, a...

In this study we have retrieved the line intensities, self broadened widths, pressure-induced shifts and selected line mixing coefficients for 20 R-branch transitions in the m1 + m2 + m4 + m5 band of acetylene. The spectra were recorded using our 3-channels diode laser spectrometer, a temperature controlled cell of fixed length and a second, room temperature cell. The Voigt and speed-dependent Voigt profiles with inclusion of line mixing effects were used to retrieve the line parameters. We determined the temperature dependencies for line broadening, shift and line mixing coefficients.

The Fourier transform spectrum of the CH317OH isotopologue of methanol has been recorded in the 65–1200 cm−1 spectral region at a resolution of 0.00096 cm−1 using synchrotron source radiation at the Canadian Light Source. Here we present an extension to higher torsional states of our investigation of the torsion–rotation transitions within the small-amplitude vibrational ground state, now including assignments of more than 16 500 lines involving quantum numbers in the ranges vt ⩽ 3, J ⩽ 30 and |K| ⩽ 12, as well as a study of the strong CO-stretching band centered at 1020 cm−1. Energy term values have been determined for assigned ground and CO-stretching levels by use of the Ritz program, and have been fitted to series expansions in powers of J(J + 1) to determine substate origins and effective B values. Several Fermi anharmonic and Coriolis level-crossing resonances coupling the CO stretch with high torsional ground-state levels have been identified and characterized. The study is motivated by astrophysical applications, with a principal aim being the compilation of an extensive set of energy term values to permit prediction of astronomically observable sub-millimetre transitions to within an uncertainty of a few MHz.

The degenerate fundamental vibrational level v5 = 1 (975.51 cm−1, E symmetry) and the overtone vibrational level v6 = 2 (1004.06/1005.98 cm−1, A1 + E symmetry) were reinvestigated with inclusion of their inter-vibrational couplings: the anharmonic Fermi interaction ( Δ K = 0 , Σ t Δ l t = Δ l 5 + Δ l 6 = ± 3 ), the second-order Coriolis resonance ( Δ K = ± 1 , Σ t Δ l t = ± 1 ), and the second-order α-resonance ( Δ K = ∓ 2 , Σ t Δ l t = ± 1 ). This required significant extension of assignments to high J and K rotational states where resonant crossings due to the latter two interactions occur. The newly assigned data from Fourier-transform IR spectroscopy were combined with rotational and laser-sideband rovibrational data pertaining to the v5 = 1 vibrational level, which were used already in a previous analysis, in a fully quantitative simultaneous fit.

Line positions, Lorentz air-broadened half width and air pressure-induced shift coefficients have been measured for nearly 200 transitions in the ν 4 band of 13 CH 4 from high-resolution spectra recorded with the McMath-Pierce Fourier transform spectrometer. Three room temperature spectra of 13 CH 4 used in the previous study of Malathy Devi et al. (Air-broadened Lorentz halfwidths and pressure-induced line shifts in the ν 4 band of 13 CH 4 . Appl. Opt. 1988; 27: 2296–2308) were analyzed together with a large number of additional spectra of self- and air-broadened CH 4 recorded at 210–314 K and one room-temperature spectrum of self-broadened 13 CH 4 . Analyses applying the multispectrum nonlinear least squares fitting technique were performed to retrieve the spectral line parameters. In addition to air-broadened half width and shift coefficients, self-broadened half width and shift coefficients were determined for at least 56 13 CH 4 ν 4 transitions. Off-diagonal relaxation matrix element coefficients for air-broadened line mixing were also determined for 28 pairs of P and R transitions in a number of J manifolds, and mixing parameters for self-broadening were also determined for some of these pairs. Temperature-dependences of the pressure-induced shift and mixing parameters for the 13 CH 4 lines could not be determined from the spectra used in the present analysis, but temperature dependences of the half width coefficients were determined for the strongest transitions. The results of this study are compared with other studies of air- and self-broadened 13 CH 4 and 12 CH 4 .

The McMath-Pierce Fourier transform spectrometer located at the National Solar Observatory (NSO) on Kitt Peak, Arizona, was used to record infrared high resolution absorption spectra of CO 2 spectra broadened by O 2 . These spectra were analyzed to measure O 2 -broadened half-width coefficients, O 2 -induced pressure-shift coefficients and speed dependent parameters for transitions in the 30013←00001 and 30012←00001 bands of 16 O 12 C 16 O located near 6227 and 6348 cm −1 , respectively. All spectra were obtained at room temperature using the long path, 6 m base path White cell available at NSO. A multispectrum nonlinear least-squares fitting algorithm employing Voigt line shapes modified to include line mixing and speed dependence was used to fit simultaneously a total of 19 spectra in the 6120–6280 cm −1 (30013←00001) and 6280–6395 cm −1 (30012←00001) spectral regions. 16 of the 19 spectra analyzed in this work were self broadened and three spectra were lean mixtures of CO 2 in O 2 . The volume mixing ratios of CO 2 in the three spectra varied between 0.06 and 0.1. Lorentz half-width and pressure-induced shift coefficients were measured for all transitions in the P(50)–R(50) range in both vibrational bands. The results obtained from present analysis have been compared with measurements available in the literature for self-, air-, oxygen- and argon-broadening. No significant differences were observed between the broadening and shift coefficients of the two bands. The N 2 -broadened half-width and pressure-shift coefficients were computed from measured air- and O 2 -broadened width and shift coefficients.

The Fourier transform spectrum of the isotopologue of methanol has been recorded in the 120–350 cm−1 far-infrared region at a resolution of 0.00096 cm−1 using synchrotron source radiation at the Canadian Light Source. The study, motivated by astrophysical applications, is aimed at generating a sufficiently accurate set of energy level term values for the ground vibrational state to allow prediction of the centres of the quadrupole hyperfine multiplets for astronomically observable sub-millimetre transitions to within an uncertainty of a few MHz. To expedite transition identification, a new function was added to the Ritz program in which predicted spectral line positions were generated by an adjustable interpolation between the known assignments for the and isotopologues. By displaying the predictions along with the experimental spectrum on the computer monitor and adjusting the predictions to match observed features, rapid assignment of numerous sub-bands was possible. The least squares function of the Ri...

Accurate values for line positions, absolute line intensities, self-broadened half width and self-pressure-induced shift coefficients have been measured for over 400 allowed and forbidden transitions in the ν4 band of methane (12CH4). Temperature dependences of half width and pressure-induced shift coefficients were also determined for many of these transitions. The spectra used in this study were recorded at temperatures between 210 and 314 K using the National Solar Observatory's 1 m Fourier transform spectrometer at the McMath-Pierce solar telescope. The complete data set included 60 high-resolution (0.006–0.01 cm−1) absorption spectra of pure methane and methane mixed with dry air. The analysis was performed using a multispectrum nonlinear least squares curve fitting technique where a number of spectra (20 or more) were fit simultaneously in spectral intervals 5–15 cm−1 wide. In addition to the line broadening and shift parameters, line mixing coefficients (using the off-diagonal relaxation matrix element formalism) were determined for more than 50 A-, E-, and F-species transition pairs in J manifolds of the P- and R-branches. The measured self-broadened half width and self-shift coefficients, their temperature dependences and the line mixing parameters are compared to self-broadening results available in the literature and to air-broadened parameters determined for these transitions from the same set of spectra.

Using a Fourier transform spectrometer setup we have measured the self-broadened half width, pressure shift, and line asymmetry coefficients for transitions in the 30012’00001 and 30013’00001 vibrational bands of carbon dioxide for four different temperatures. A total of 46 pure CO2 spectra were recorded at 0.008 and 0.009 cm � 1 resolution and at pressures varying from a few Torr to nearly an atmosphere. The individual spectral line profiles have been fitted by a Voigt profile and a speeddependent Voigt profile, to which we have added dispersion profiles to account for weak line mixing. A comparison of the sets of results obtained for each band showed no vibrational dependence of the broadening coefficients. The self-broadening and selfshift coefficients are compared to semiclassical calculations based on the Robert– Bonamy formalism and were found to be in good agreement. The line asymmetry results are compared to line mixing calculations based on the Energy Corrected Sudden (ECS) and Exponential Power Gap models.