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Papers by Praveenkumar Boopalachandran

Research paper thumbnail of Spectroscopic studies of pyridine and its isotopomer, 2-fluoro- and 3-fluoropyridine, 1,3-butadiene and its isotopomers

Spectroscopic Studies of Pyridine and its Isotopomer, 2-Fluoroand 3-Fluoropyridine, 1,3-Butadiene... more Spectroscopic Studies of Pyridine and its Isotopomer, 2-Fluoroand 3-Fluoropyridine, 1,3-Butadiene and Its Isotopomers. (December 2011) Praveenkumar Boopalachandran, B.Tech., University of Madras, India; M.S., Texas A&M University-Commerce; M.S., Texas A&M University Chair of Advisory Committee: Dr. Jaan Laane The infrared, Raman and ultraviolet spectra of pyridine-d0 and pyridine-d5 were recorded and assigned with a focus on the low-frequency vibrational modes in the S1(n,π*) electronic excited state. An energy map for the low-frequency modes was constructed and the data for the ν18 mode allowed a highly anharmonic one-dimensional potential energy function to be determined for the S1 excited state. In this S1(n,π*) state, pyridine is quasi-planar and very floppy with a barrier to planarity of 3 cm. The infrared, Raman and ultraviolet spectra of 2-fluoropyridine (2FPy) and 3fluoropyridine (3FPy) have been collected and assigned. For 2FPy about 150 bands were observed for the transiti...

Research paper thumbnail of Simultaneous measurement of the molecular weight distribution and 5-ethylidene-2-norbornene content across the molecular weight distribution of ethylene-propylene-diene terpolymer via a new size exclusion chromatography-ultraviolet-refractive index method

Journal of Applied Polymer Science, 2016

Research paper thumbnail of Gel Formation in Urethane Liquid Oligomers

Bulletin of the American Physical Society, 2020

Research paper thumbnail of A STUDY OF NbCr AND NbCr$^{-}$ BY ANION PHOTOELECTRON SPECTROSCOPY

Author Institution: Department of Chemistry, University of Minnesota, Minneapolis, MN 55455

Research paper thumbnail of GAS PHASE RAMAN SPECTRA OF BUTADIENE AND BUTADIENE-d$_{6}$ AND THE INTERNAL ROTATION POTENTIAL ENERGY FUNCTION

L.~Carreira, J.~Phys.~Chem. 62, 3851 (1975).R.~Engeln, D.~Consalvo, and J.~Reuss, J.~Chem.~Phys. ... more L.~Carreira, J.~Phys.~Chem. 62, 3851 (1975).R.~Engeln, D.~Consalvo, and J.~Reuss, J.~Chem.~Phys. 160, 427 (1992).D.~Feller and N.~C.~Craig, J.~Phys.~Chem. 113, 1601 (2009).

Research paper thumbnail of A Combination of FTIR , MS and NMR Techniques to Characterize an Aqueous Wax Emulsion

In this paper, a combination of FTIR, Thermal Desorption/Pyrolysis GC/MS, KIDS MS, ESI MS, and C ... more In this paper, a combination of FTIR, Thermal Desorption/Pyrolysis GC/MS, KIDS MS, ESI MS, and C NMR techniques was utilized to characterize an aqueous wax emulsion. Analytical data suggests that this aqueous wax emulsion consists of 94.8 wt% paraffin, 3.2 wt% diethylene glycol butyl ether and 2.0 wt% oleic acid (water free basis). Since this is a water based emulsion system, no attempts were made to determine the amount of water. The detection of NH3 by GC/MS and determination of 547 ppm total nitrogen by TNA (Total Nitrogen Analysis) led to the estimation of about 1328 ppm NH4OH in the sample. Introduction Aqueous wax emulsions are widely available and are generally used to provide an improved appearance such as a glossy surface on buffing. The surface wax protects the treated area from abrasion and stains, and provides improved weather resistance to water. As a result, many metal and wood surfaces are treated with commercially available aqueous paraffin wax emulsions. An aqueous ...

Research paper thumbnail of Catalytic studies of supported Pd-Au catalysts

Research paper thumbnail of A STUDY OF NbMo AND NbMo$^{-}$ BY ANION PHOTOELECTRON SPECTROSCOPY

Author Institution: Department of Chemistry, University of Minnesota, Minneapolis, MN 55455

Research paper thumbnail of Failure Analysis of Polyethylene Products Using Microscopy

Microscopy and Microanalysis

Research paper thumbnail of Probing the effect of polymer molecular weight on penetration into the wood cell wall using polyethylenimine (PEI) as a model compound

Journal of microscopy, 2018

Decking is one of the largest applications for the treated wood market. The most challenging prop... more Decking is one of the largest applications for the treated wood market. The most challenging property to obtain for treated wood is dimensional stability, which can be achieved, in part, by cell wall bulking, cell wall polymer crosslinking and removal of hygroscopic components in the cell wall. A commonly accepted key requirement is for the actives to infuse through the cell wall, which has a microporosity of ∼5-13 nm. Equally as challenging is being able to measure and quantify the cell wall penetration. Branched polyethylenimine (PEI) was studied as a model polymer for penetration due to its water solubility, polarity, variable molecular weight ranges, and ability to form a chelation complex with preservative metals to treat lumbers. Two different molecular weight polyethylenimines (PEI), one with a weight average molecular weight (Mw) equal to 800 Da and the other 750 000 Da, were investigated for penetration by microscopy and spectroscopy techniques. Analytical methods were deve...

Research paper thumbnail of Capabilities of a New Sample Preparation Method for Probing Polymer Penetration and Localization into Wood Without Embedding

Microscopy and Microanalysis

Research paper thumbnail of Thermally Induced Cross-Linking and Degradation Reactions of Benzocyclobutene-Based Polymers

Research paper thumbnail of Dimensional stability and hardness improvement of southern yellow pine wood using divinylbenzene dioxide

European Journal of Wood and Wood Products

Research paper thumbnail of A STUDY OF NbMo AND NbMo$^{-}$ BY ANION PHOTOELECTRON SPECTROSCOPY

Research paper thumbnail of Ultraviolet, Infrared, and Raman Spectra of Pyridine and Its Fluoro Derivatives

Research paper thumbnail of Catalytic studies of supported Pd-Au catalysts

Research paper thumbnail of Iron(III)-Catalyzed Chain Growth Reactions of Polymeric Methylene Diphenyl Diisocyanate

Research paper thumbnail of Anharmonic Vibrational Analysis of the Infrared and Raman Gas-Phase Spectra of s-trans - and s-gauche -1,3-Butadiene

The Journal of Physical Chemistry A, 2015

Research paper thumbnail of ANION PHOTOELECTRON SPECTROSCOPIC STUDIES OF NbCr(CO)n− (n = 2,3) HETEROBIMETALLIC CARBONYL COMPLEXES

Proceedings of the 70th International Symposium on Molecular Spectroscopy, 2015

Research paper thumbnail of Raman Spectra and the Potential Energy Function for the Internal Rotation of 1,3Butadiene and its Isotopomers

The gas-phase Raman spectra of 1,3-butadiene-d0, 2,3-d2, 1,1,4,4-d4, and --d6 have been collected... more The gas-phase Raman spectra of 1,3-butadiene-d0, 2,3-d2, 1,1,4,4-d4, and --d6 have been collected with CCD detection with numerous scans of ten hours or more. For each isotopomer eight Raman transitions in the 240-330 cm-1 region corresponding to double quantum jumps of the Au internal rotation (nu13) were observed for the trans conformer. Weaker bands in the 170-260 cm-1 region were assigned to the gauche conformation, which lies at higher electronic energy. A periodic potential function for the internal rotation, which fits the data for all the isotopomers, was determined. This function shows the gauche form to be 966 cm-1 higher in energy and the barrier between the trans and gauche structures to be 2055 cm-1. The cis structure has an energy 408 cm-1 higher than the gauche. Fourteen combination band or hot band series involving nu13 for the trans conformer were also observed, and these allow the internal rotation levels in various excited vibrational states to be determined.

Research paper thumbnail of Spectroscopic studies of pyridine and its isotopomer, 2-fluoro- and 3-fluoropyridine, 1,3-butadiene and its isotopomers

Spectroscopic Studies of Pyridine and its Isotopomer, 2-Fluoroand 3-Fluoropyridine, 1,3-Butadiene... more Spectroscopic Studies of Pyridine and its Isotopomer, 2-Fluoroand 3-Fluoropyridine, 1,3-Butadiene and Its Isotopomers. (December 2011) Praveenkumar Boopalachandran, B.Tech., University of Madras, India; M.S., Texas A&M University-Commerce; M.S., Texas A&M University Chair of Advisory Committee: Dr. Jaan Laane The infrared, Raman and ultraviolet spectra of pyridine-d0 and pyridine-d5 were recorded and assigned with a focus on the low-frequency vibrational modes in the S1(n,π*) electronic excited state. An energy map for the low-frequency modes was constructed and the data for the ν18 mode allowed a highly anharmonic one-dimensional potential energy function to be determined for the S1 excited state. In this S1(n,π*) state, pyridine is quasi-planar and very floppy with a barrier to planarity of 3 cm. The infrared, Raman and ultraviolet spectra of 2-fluoropyridine (2FPy) and 3fluoropyridine (3FPy) have been collected and assigned. For 2FPy about 150 bands were observed for the transiti...

Research paper thumbnail of Simultaneous measurement of the molecular weight distribution and 5-ethylidene-2-norbornene content across the molecular weight distribution of ethylene-propylene-diene terpolymer via a new size exclusion chromatography-ultraviolet-refractive index method

Journal of Applied Polymer Science, 2016

Research paper thumbnail of Gel Formation in Urethane Liquid Oligomers

Bulletin of the American Physical Society, 2020

Research paper thumbnail of A STUDY OF NbCr AND NbCr$^{-}$ BY ANION PHOTOELECTRON SPECTROSCOPY

Author Institution: Department of Chemistry, University of Minnesota, Minneapolis, MN 55455

Research paper thumbnail of GAS PHASE RAMAN SPECTRA OF BUTADIENE AND BUTADIENE-d$_{6}$ AND THE INTERNAL ROTATION POTENTIAL ENERGY FUNCTION

L.~Carreira, J.~Phys.~Chem. 62, 3851 (1975).R.~Engeln, D.~Consalvo, and J.~Reuss, J.~Chem.~Phys. ... more L.~Carreira, J.~Phys.~Chem. 62, 3851 (1975).R.~Engeln, D.~Consalvo, and J.~Reuss, J.~Chem.~Phys. 160, 427 (1992).D.~Feller and N.~C.~Craig, J.~Phys.~Chem. 113, 1601 (2009).

Research paper thumbnail of A Combination of FTIR , MS and NMR Techniques to Characterize an Aqueous Wax Emulsion

In this paper, a combination of FTIR, Thermal Desorption/Pyrolysis GC/MS, KIDS MS, ESI MS, and C ... more In this paper, a combination of FTIR, Thermal Desorption/Pyrolysis GC/MS, KIDS MS, ESI MS, and C NMR techniques was utilized to characterize an aqueous wax emulsion. Analytical data suggests that this aqueous wax emulsion consists of 94.8 wt% paraffin, 3.2 wt% diethylene glycol butyl ether and 2.0 wt% oleic acid (water free basis). Since this is a water based emulsion system, no attempts were made to determine the amount of water. The detection of NH3 by GC/MS and determination of 547 ppm total nitrogen by TNA (Total Nitrogen Analysis) led to the estimation of about 1328 ppm NH4OH in the sample. Introduction Aqueous wax emulsions are widely available and are generally used to provide an improved appearance such as a glossy surface on buffing. The surface wax protects the treated area from abrasion and stains, and provides improved weather resistance to water. As a result, many metal and wood surfaces are treated with commercially available aqueous paraffin wax emulsions. An aqueous ...

Research paper thumbnail of Catalytic studies of supported Pd-Au catalysts

Research paper thumbnail of A STUDY OF NbMo AND NbMo$^{-}$ BY ANION PHOTOELECTRON SPECTROSCOPY

Author Institution: Department of Chemistry, University of Minnesota, Minneapolis, MN 55455

Research paper thumbnail of Failure Analysis of Polyethylene Products Using Microscopy

Microscopy and Microanalysis

Research paper thumbnail of Probing the effect of polymer molecular weight on penetration into the wood cell wall using polyethylenimine (PEI) as a model compound

Journal of microscopy, 2018

Decking is one of the largest applications for the treated wood market. The most challenging prop... more Decking is one of the largest applications for the treated wood market. The most challenging property to obtain for treated wood is dimensional stability, which can be achieved, in part, by cell wall bulking, cell wall polymer crosslinking and removal of hygroscopic components in the cell wall. A commonly accepted key requirement is for the actives to infuse through the cell wall, which has a microporosity of ∼5-13 nm. Equally as challenging is being able to measure and quantify the cell wall penetration. Branched polyethylenimine (PEI) was studied as a model polymer for penetration due to its water solubility, polarity, variable molecular weight ranges, and ability to form a chelation complex with preservative metals to treat lumbers. Two different molecular weight polyethylenimines (PEI), one with a weight average molecular weight (Mw) equal to 800 Da and the other 750 000 Da, were investigated for penetration by microscopy and spectroscopy techniques. Analytical methods were deve...

Research paper thumbnail of Capabilities of a New Sample Preparation Method for Probing Polymer Penetration and Localization into Wood Without Embedding

Microscopy and Microanalysis

Research paper thumbnail of Thermally Induced Cross-Linking and Degradation Reactions of Benzocyclobutene-Based Polymers

Research paper thumbnail of Dimensional stability and hardness improvement of southern yellow pine wood using divinylbenzene dioxide

European Journal of Wood and Wood Products

Research paper thumbnail of A STUDY OF NbMo AND NbMo$^{-}$ BY ANION PHOTOELECTRON SPECTROSCOPY

Research paper thumbnail of Ultraviolet, Infrared, and Raman Spectra of Pyridine and Its Fluoro Derivatives

Research paper thumbnail of Catalytic studies of supported Pd-Au catalysts

Research paper thumbnail of Iron(III)-Catalyzed Chain Growth Reactions of Polymeric Methylene Diphenyl Diisocyanate

Research paper thumbnail of Anharmonic Vibrational Analysis of the Infrared and Raman Gas-Phase Spectra of s-trans - and s-gauche -1,3-Butadiene

The Journal of Physical Chemistry A, 2015

Research paper thumbnail of ANION PHOTOELECTRON SPECTROSCOPIC STUDIES OF NbCr(CO)n− (n = 2,3) HETEROBIMETALLIC CARBONYL COMPLEXES

Proceedings of the 70th International Symposium on Molecular Spectroscopy, 2015

Research paper thumbnail of Raman Spectra and the Potential Energy Function for the Internal Rotation of 1,3Butadiene and its Isotopomers

The gas-phase Raman spectra of 1,3-butadiene-d0, 2,3-d2, 1,1,4,4-d4, and --d6 have been collected... more The gas-phase Raman spectra of 1,3-butadiene-d0, 2,3-d2, 1,1,4,4-d4, and --d6 have been collected with CCD detection with numerous scans of ten hours or more. For each isotopomer eight Raman transitions in the 240-330 cm-1 region corresponding to double quantum jumps of the Au internal rotation (nu13) were observed for the trans conformer. Weaker bands in the 170-260 cm-1 region were assigned to the gauche conformation, which lies at higher electronic energy. A periodic potential function for the internal rotation, which fits the data for all the isotopomers, was determined. This function shows the gauche form to be 966 cm-1 higher in energy and the barrier between the trans and gauche structures to be 2055 cm-1. The cis structure has an energy 408 cm-1 higher than the gauche. Fourteen combination band or hot band series involving nu13 for the trans conformer were also observed, and these allow the internal rotation levels in various excited vibrational states to be determined.