Infrared spectra of dimethylnaphthalenes in the gas phase
نویسندگان
چکیده
We report the infrared spectra at 0.5 cm 1 resolution of three dimethylnaphthalenes (DMNs), namely 1,5-DMN, 1,6-DMN and 2,6-DMN in the gas phase at an elevated temperature recorded with the help of a variable path-length cell. DFT calculations have been carried out at B3LYP levels of theory with 6-31G* as basis set to determine the harmonic frequencies and intensities of the DMNs to assign the experimentally observed spectra. We have compared the experimentally observed and theoretically calculated spectra of the dimethylnaphthalenes and assignments have been made. The observed and predicted frequencies and relative intensities are generally in good agreement. The intense aromatic C–H out-ofplane bending vibration observed around 800 cm 1 and three methyl C–H symmetric and asymmetric stretching vibrations around 2900 cm 1 have been recognized as unique bands to identify various DMNs in a mixture. The high-resolution IR spectroscopy of these three important polycyclic aromatic hydrocarbons which are present in the atmosphere have been discussed. # 2008 Elsevier B.V. All rights reserved.
منابع مشابه
Theoretical Studies of the Vibrational Spectra and Molecular Structures of Dosulepin and Doxepin
Dosulepin and doxepin are tricyclic antidepressants. The molecular geometries, harmonic vibrational frequencies, quantum chemical parameters and thermodynamic properties of dosulepin and doxepin were calculated by Generalized Gradient Approximation methods developed by Perdew and Wang (GGA-PW91) and Becke-Lee-Yang-Parr (GGA-BLYP) in the gas phase and solution media. The local reactivity of thes...
متن کاملExperimental vibrational spectra of gas-phase tantalum cluster cations.
We present gas-phase infrared spectra of tantalum cluster cations containing 6-20 atoms. Infrared multiple photon dissociation of their complexes with argon atoms is used to obtain vibrational spectra in the region between 90 and 305 cm(-1). Many spectra have features in common with the vibrational spectra of the lighter homologs, vanadium and niobium, pointing to a common cluster growth mechan...
متن کاملStability analysis of stratified two-phase liquid-gas flow in a horizontal pipe
This study aimed at linear stability analysis of the stratified two-phase liquid-gas flow in a horizontal pipe. First, equations governing the linear stability of flow in each phase and boundary conditions were obtained. The governing equations were eigenvalue Orr Sommerfeld equations which are difficult and stiff problems to solve. After obtaining the velocity profiles of the gas and liquid ph...
متن کاملStructure determination of gas-phase niobium and tantalum carbide nanocrystals via infrared spectroscopy.
Niobium and tantalum carbide clusters have been isolated in the gas phase and irradiated with intense tunable infrared (IR) light. Stable neutral clusters are selectively ionized and subsequently detected in a mass spectrometer. By tuning the IR frequency, infrared multiphoton absorption spectra are obtained for a whole range of clusters. These mass-selective IR spectra lead to insights into th...
متن کاملDatabase of Quantitative Infrared Spectra of Gases
The foundation of QASoft is the database of quantitative reference spectra. When the development of QASoft was begun some 10 years ago there were no available quantitative gas phase spectra. The available gas spectra such as those in the collections from Sadtler, Aldrich or EPA were recorded only for purposes of molecule detection and identification, not for measurement. In almost all cases the...
متن کامل