IIT Kanpur

Education / Work History

Research Topic / Interest

Contact me to know my current interests.

Publications

These include only those published in our lab.

  1. Effect of Isotope Substitution in Binary Liquids with Thermal-Lens Spectroscopy. I. Bhattacharyya, P. Kumar, and D. Goswami, Chemical Physics Letters 598, 35–38 (2014) [Abstract] [PDF] [BibTeX]

    Abstract: Effect of isotope substitution from the modulation of Thermal-Lens (TL) signals in binary liquid mixtures is explored using femtosecond pump–probe mode-mismatched Z-scan TL spectroscopy. Binary solutions of water and heavy water with pure methanol at various concentrations are used for the study, where pure methanol acts as the TL marker across the different samples. The TL signal is found to be effectively modulated by isotope substitution under the experimental conditions, indicating that TL signal depends on hydrogen bonding.

     BibTeX: @article{bhattacharyyaEffectIsotopeSubstitution2014,
      title = {Effect of Isotope Substitution in Binary Liquids with {{Thermal-Lens}} Spectroscopy},
      author = {Bhattacharyya, Indrajit and Kumar, Pardeep and Goswami, Debabrata},
      date = {2014-04-08},
      journaltitle = {Chemical Physics Letters},
      shortjournal = {Chemical Physics Letters},
      volume = {598},
      pages = {35--38},
      issn = {0009-2614},
      doi = {10/f5xrr2},
      url = {http://pc.cd/PORctalK},
      urldate = {2019-08-02}
    }
    
  2. Probing Intermolecular Interaction through Thermal-Lens Spectroscopy. I. Bhattacharyya, P. Kumar, and D. Goswami, The Journal of Physical Chemistry B 115(2), 262–268 (2011) [Abstract] [PDF] [BibTeX]

    Abstract: Binary liquid mixtures are studied using femtosecond pump−probe thermal-lens (TL) spectroscopy. Changes in the measured TL signals as a function of relative concentration of binary mixtures show that these result from a combined effect of physical and molecular properties of the constituent binary liquids. The experimental TL values deviate from the ones calculated from phenomenological equations. These, we argue, are due to an underestimation of the influence of molecular interactions when the TL signals are calculated by using physical parameters only.

     BibTeX: @article{bhattacharyyaProbingIntermolecularInteraction2011,
      title = {Probing {{Intermolecular Interaction}} through {{Thermal-Lens Spectroscopy}}},
      author = {Bhattacharyya, Indrajit and Kumar, Pardeep and Goswami, Debabrata},
      date = {2011-01-20},
      journaltitle = {The Journal of Physical Chemistry B},
      shortjournal = {J. Phys. Chem. B},
      volume = {115},
      number = {2},
      pages = {262--268},
      issn = {1520-6106},
      doi = {10/d9mz5f},
      url = {https://doi.org/10.1021/jp1062429},
      urldate = {2019-08-14}
    }
    
  3. Thermal-Lens Spectroscopy in Binary Liquids Mixtures. I. Bhattacharyya, P. Kumar, and D. Goswami, in Frontiers in Optics 2010/Laser Science XXVI (2010), Paper FWX1 (Optical Society of America, 2010), p. FWX1 [Abstract] [PDF] [BibTeX]

    Abstract: Using femtosecond pump-probe thermal-lens (TL) spectroscopy, experiments in binary-mixtures are presented where trends in TL are modulated by physical and molecular properties. Deviations of experimental results from phenomenological models indicate possible underestimation of molecular interactions.

     BibTeX: @inproceedings{bhattacharyyaThermalLensSpectroscopyBinary2010,
      title = {Thermal-{{Lens}} Spectroscopy in Binary Liquids Mixtures},
      booktitle = {Frontiers in {{Optics}} 2010/{{Laser Science XXVI}} (2010), Paper {{FWX1}}},
      author = {Bhattacharyya, Indrajit and Kumar, Pardeep and Goswami, Debabrata},
      date = {2010-10-24},
      pages = {FWX1},
      publisher = {{Optical Society of America}},
      doi = {10/gf6c8z},
      url = {https://www.osapublishing.org/abstract.cfm?uri=FiO-2010-FWX1},
      urldate = {2019-08-14},
      eventtitle = {Frontiers in {{Optics}}}
    }
    
  4. Measurement Constraints in Laser Based Thermal Lens Experiments. D. Goswami and P. Kumar, in International Conference on Optics and Photonics 2015 (International Society for Optics and Photonics, 2015), 9654, p. 965406 [Abstract] [PDF] [BibTeX]

    Abstract: Importance of various measurement schemes in studying thermal lens (TL) signal for laser based TL experiments is explored. We show that two different measurement schemes can result in two contrasting outcomes. In one experiment, two measurement schemes show diverging results for TL signal measurements, which gives a convoluted result and in the other experiment, the two measurement schemes give a converging result.

     BibTeX: @inproceedings{goswamiMeasurementConstraintsLaser2015,
      title = {Measurement Constraints in Laser Based Thermal Lens Experiments},
      booktitle = {International {{Conference}} on {{Optics}} and {{Photonics}} 2015},
      author = {Goswami, Debabrata and Kumar, Pardeep},
      date = {2015-06-15},
      volume = {9654},
      pages = {965406},
      publisher = {{International Society for Optics and Photonics}},
      doi = {10/gf5msn},
      url = {https://www.spiedigitallibrary.org/conference-proceedings-of-spie/9654/965406/Measurement-constraints-in-laser-based-thermal-lens-experiments/10.1117/12.2192167.short},
      urldate = {2019-08-01},
      eventtitle = {International {{Conference}} on {{Optics}} and {{Photonics}} 2015}
    }
    
  5. Effect of Molecular Structural Isomers in Thermal Lens Spectroscopy. P. Kumar, S. Dinda, and D. Goswami, Chemical Physics Letters 601, 163–167 (2014) [Abstract] [PDF] [BibTeX]

    Abstract: We explore the importance of molecular structure on thermal lens (TL) spectroscopy by measuring the effects of molecular isomerization on TL measurements. In particular, we present a case study for all the structural isomers of butanol, namely, normal-butanol (n-BuOH), secondary-butanol (s-BuOH), isobutanol (i-BuOH) and tertiary-butanol (t-BuOH). We argue that the molecular isomerization influences the heat convection process in two possible ways: one being a change in the molecular surface area and the other being the steric hindrance. We show that n-BuOH has the highest capability to transfer heat by convection. Branching in the molecular structure renders the system sluggish as it makes the molecular motion successively retarded due to an increase in the mean free path. This we have defined as the molecular drift that slows under thermal conditions. In our studied isomers, therefore, t-BuOH drifts the slowest.

     BibTeX: @article{kumarEffectMolecularStructural2014,
      title = {Effect of Molecular Structural Isomers in Thermal Lens Spectroscopy},
      author = {Kumar, Pardeep and Dinda, Sirshendu and Goswami, Debabrata},
      date = {2014-05},
      journaltitle = {Chemical Physics Letters},
      shortjournal = {Chemical Physics Letters},
      volume = {601},
      pages = {163--167},
      issn = {00092614},
      doi = {10/gf6bk6},
      url = {https://linkinghub.elsevier.com/retrieve/pii/S0009261414002620},
      urldate = {2019-08-12}
    }
    
  6. Importance of Molecular Heat Convection in Time Resolved Thermal Lens Study of Highly Absorbing Samples. P. Kumar, A. Khan, and D. Goswami, Chemical Physics 441, 5–10 (2014) [Abstract] [PDF] [BibTeX]

    Abstract: Our experimental study shows that in the case of strongly absorbing samples, the time resolved thermal lens (TL) signal has a distinctive new feature. Existing TL models that are only based on heat conduction cannot explain this behavior. We have therefore developed a more comprehensive model that can also explain this additional feature in the TL of strongly absorbing samples. Our model is also capable of explaining our experimental results that show how the molecular size affects the molecular heat convection.

     BibTeX: @article{kumarImportanceMolecularHeat2014,
      title = {Importance of Molecular Heat Convection in Time Resolved Thermal Lens Study of Highly Absorbing Samples},
      author = {Kumar, Pardeep and Khan, Arbaz and Goswami, Debabrata},
      date = {2014-09-30},
      journaltitle = {Chemical Physics},
      shortjournal = {Chemical Physics},
      volume = {441},
      pages = {5--10},
      issn = {0301-0104},
      doi = {10/f6kr7q},
      url = {http://www.sciencedirect.com/science/article/pii/S0301010414001724},
      urldate = {2019-08-01}
    }
    
  7. Importance of Molecular Structure on the Thermophoresis of Binary Mixtures. P. Kumar and D. Goswami, The Journal of Physical Chemistry B 118(51), 14852–14859 (2014) [Abstract] [PDF] [BibTeX]

    Abstract: Using thermal lens spectroscopy, we study the role of molecular structural isomers of butanol on the thermophoresis (or Soret effect) of binary mixtures of methanol in butanol. In this study, we show that the thermal lens signal due to the Soret effect changes its sign for all the different concentrations of binary mixtures of butanol with methanol except for the one containing tertiary-butanol. The magnitude and sign of the Soret coefficients strongly depend on the molecular structure of the isomers of butanol in the binary mixture with methanol. This isomerization dependence is in stark contrast to the expected mass dependence of the Soret effect.

     BibTeX: @article{kumarImportanceMolecularStructure2014,
      title = {Importance of {{Molecular Structure}} on the {{Thermophoresis}} of {{Binary Mixtures}}},
      author = {Kumar, Pardeep and Goswami, Debabrata},
      date = {2014-12-26},
      journaltitle = {The Journal of Physical Chemistry B},
      shortjournal = {J. Phys. Chem. B},
      volume = {118},
      number = {51},
      pages = {14852--14859},
      issn = {1520-6106},
      doi = {10/gf5ms6},
      url = {https://doi.org/10.1021/jp5079604},
      urldate = {2019-08-01}
    }
    
  8. Thermal-Lens Spectroscopy in Binary Liquids Mixtures: Effect of Isotope Substitution. P. Kumar, I. Bhattacharyya, and D. Goswami, in Frontiers in Optics 2011/Laser Science XXVII (2011), Paper JTuA25 (Optical Society of America, 2011), p. JTuA25 [Abstract] [PDF] [BibTeX]

    Abstract: Using femtosecond pump-probe thermal lens (TL) spectroscopy, we show that the effect of isotope substitution can be monitored through a modulation of TL signals in binary liquids showing the important of molecular properties on TL.

     BibTeX: @inproceedings{kumarThermalLensSpectroscopyBinary2011,
      title = {Thermal-{{Lens Spectroscopy}} in {{Binary Liquids Mixtures}}: {{Effect}} of {{Isotope Substitution}}},
      shorttitle = {Thermal-{{Lens Spectroscopy}} in {{Binary Liquids Mixtures}}},
      booktitle = {Frontiers in {{Optics}} 2011/{{Laser Science XXVII}} (2011), Paper {{JTuA25}}},
      author = {Kumar, Pardeep and Bhattacharyya, Indrajit and Goswami, Debabrata},
      date = {2011-10-16},
      pages = {JTuA25},
      publisher = {{Optical Society of America}},
      doi = {10/gf5nqg},
      url = {https://www.osapublishing.org/abstract.cfm?uri=FiO-2011-JTuA25},
      urldate = {2019-08-02},
      eventtitle = {Frontiers in {{Optics}}}
    }
    
  9. Unusual Behavior of Thermal Lens in Alcohols. P. Kumar, S. Dinda, A. Chakraborty, and D. Goswami, Physical Chemistry Chemical Physics 16(24), 12291–12298 (2014) [Abstract] [PDF] [BibTeX]

    Abstract: We use a femtosecond pump–probe Z-scan technique to measure the thermal lens (TL) signal in a homologous series of primary alcohols. The trend in these experimentally measured TL signals deviates in a counterintuitive manner from the ones calculated using theoretical models that are only based on the macroscopic parameters. Introspection shows that the present TL theories are based on heat conduction for low absorbing samples without considering any convective mode of heat transfer. Our studies on highly absorbing samples indicate the importance of convective mode of heat transfer in TL studies.

     BibTeX: @article{kumarUnusualBehaviorThermal2014,
      title = {Unusual Behavior of Thermal Lens in Alcohols},
      author = {Kumar, Pardeep and Dinda, Sirshendu and Chakraborty, Atanu and Goswami, Debabrata},
      date = {2014},
      journaltitle = {Physical Chemistry Chemical Physics},
      volume = {16},
      number = {24},
      pages = {12291--12298},
      doi = {10/gf5npt},
      url = {https://pubs.rsc.org/en/content/articlelanding/2014/cp/c4cp00895b},
      urldate = {2019-08-02}
    }
    
  10. Measurement Constraints in Laser Based Thermal Lens Experiments. D. Goswami and P. Kumar, in International Conference on Optics and Photonics 2015 (International Society for Optics and Photonics, 2015), 9654, p. 965406 [Abstract] [PDF] [BibTeX]

    Abstract: Importance of various measurement schemes in studying thermal lens (TL) signal for laser based TL experiments is explored. We show that two different measurement schemes can result in two contrasting outcomes. In one experiment, two measurement schemes show diverging results for TL signal measurements, which gives a convoluted result and in the other experiment, the two measurement schemes give a converging result.

     BibTeX: @inproceedings{goswamiMeasurementConstraintsLaser2016,
      title = {Measurement Constraints in Laser Based Thermal Lens Experiments},
      volume = {9654},
      url = {https://www.spiedigitallibrary.org/conference-proceedings-of-spie/9654/965406/Measurement-constraints-in-laser-based-thermal-lens-experiments/10.1117/12.2192167.short},
      doi = {10/gf5msn},
      eventtitle = {International {{Conference}} on {{Optics}} and {{Photonics}} 2015},
      booktitle = {International {{Conference}} on {{Optics}} and {{Photonics}} 2015},
      publisher = {{International Society for Optics and Photonics}},
      urldate = {2019-08-01},
      date = {2015-06-15},
      pages = {965406},
      author = {Goswami, Debabrata and Kumar, Pardeep}
    }
    
  11. Importance of Molecular Structure on the Thermophoresis of Binary Mixtures. P. Kumar and D. Goswami, J. Phys. Chem. B 118(51), 14852–14859 (2014) [Abstract] [PDF] [BibTeX]

    Abstract: Using thermal lens spectroscopy, we study the role of molecular structural isomers of butanol on the thermophoresis (or Soret effect) of binary mixtures of methanol in butanol. In this study, we show that the thermal lens signal due to the Soret effect changes its sign for all the different concentrations of binary mixtures of butanol with methanol except for the one containing tertiary-butanol. The magnitude and sign of the Soret coefficients strongly depend on the molecular structure of the isomers of butanol in the binary mixture with methanol. This isomerization dependence is in stark contrast to the expected mass dependence of the Soret effect.

     BibTeX: @article{kumarImportanceMolecularStructure2015,
      title = {Importance of {{Molecular Structure}} on the {{Thermophoresis}} of {{Binary Mixtures}}},
      volume = {118},
      issn = {1520-6106},
      url = {https://doi.org/10.1021/jp5079604},
      doi = {10/gf5ms6},
      number = {51},
      journaltitle = {J. Phys. Chem. B},
      urldate = {2019-08-01},
      date = {2014-12-26},
      pages = {14852-14859},
      author = {Kumar, Pardeep and Goswami, Debabrata}
    }
    
  12. Importance of Molecular Heat Convection in Time Resolved Thermal Lens Study of Highly Absorbing Samples. P. Kumar, A. Khan, and D. Goswami, Chemical Physics 441, 5–10 (2014) [Abstract] [PDF] [BibTeX]

    Abstract: Our experimental study shows that in the case of strongly absorbing samples, the time resolved thermal lens (TL) signal has a distinctive new feature. Existing TL models that are only based on heat conduction cannot explain this behavior. We have therefore developed a more comprehensive model that can also explain this additional feature in the TL of strongly absorbing samples. Our model is also capable of explaining our experimental results that show how the molecular size affects the molecular heat convection.

     BibTeX: @article{kumarImportanceMolecularHeat2015,
      title = {Importance of Molecular Heat Convection in Time Resolved Thermal Lens Study of Highly Absorbing Samples},
      volume = {441},
      issn = {0301-0104},
      url = {http://www.sciencedirect.com/science/article/pii/S0301010414001724},
      doi = {10/f6kr7q},
      journaltitle = {Chemical Physics},
      urldate = {2019-08-01},
      date = {2014-09-30},
      pages = {5-10},
      author = {Kumar, Pardeep and Khan, Arbaz and Goswami, Debabrata}
    }
    
  13. Effect of Isotope Substitution in Binary Liquids with Thermal-Lens Spectroscopy. I. Bhattacharyya, P. Kumar, and D. Goswami, Chemical Physics Letters 598, 35–38 (2014) [Abstract] [PDF] [BibTeX]

    Abstract: Effect of isotope substitution from the modulation of Thermal-Lens (TL) signals in binary liquid mixtures is explored using femtosecond pump–probe mode-mismatched Z-scan TL spectroscopy. Binary solutions of water and heavy water with pure methanol at various concentrations are used for the study, where pure methanol acts as the TL marker across the different samples. The TL signal is found to be effectively modulated by isotope substitution under the experimental conditions, indicating that TL signal depends on hydrogen bonding.

     BibTeX: @article{bhattacharyyaEffectIsotopeSubstitution2015,
      title = {Effect of Isotope Substitution in Binary Liquids with {{Thermal}}-{{Lens}} Spectroscopy},
      volume = {598},
      issn = {0009-2614},
      url = {http://pc.cd/PORctalK},
      doi = {10/f5xrr2},
      journaltitle = {Chemical Physics Letters},
      urldate = {2019-08-02},
      date = {2014-04-08},
      pages = {35-38},
      author = {Bhattacharyya, Indrajit and Kumar, Pardeep and Goswami, Debabrata}
    }
    
  14. Unusual Behavior of Thermal Lens in Alcohols. P. Kumar, S. Dinda, A. Chakraborty, and D. Goswami, Physical Chemistry Chemical Physics 16(24), 12291–12298 (2014) [Abstract] [PDF] [BibTeX]

    Abstract: We use a femtosecond pump–probe Z-scan technique to measure the thermal lens (TL) signal in a homologous series of primary alcohols. The trend in these experimentally measured TL signals deviates in a counterintuitive manner from the ones calculated using theoretical models that are only based on the macroscopic parameters. Introspection shows that the present TL theories are based on heat conduction for low absorbing samples without considering any convective mode of heat transfer. Our studies on highly absorbing samples indicate the importance of convective mode of heat transfer in TL studies.

     BibTeX: @article{kumarUnusualBehaviorThermal2015,
      langid = {english},
      title = {Unusual Behavior of Thermal Lens in Alcohols},
      volume = {16},
      url = {https://pubs.rsc.org/en/content/articlelanding/2014/cp/c4cp00895b},
      doi = {10/gf5npt},
      number = {24},
      journaltitle = {Physical Chemistry Chemical Physics},
      urldate = {2019-08-02},
      date = {2014},
      pages = {12291-12298},
      author = {Kumar, Pardeep and Dinda, Sirshendu and Chakraborty, Atanu and Goswami, Debabrata}
    }
    
  15. Thermal-Lens Spectroscopy in Binary Liquids Mixtures: Effect of Isotope Substitution. P. Kumar, I. Bhattacharyya, and D. Goswami, in Frontiers in Optics 2011/Laser Science XXVII (2011), Paper JTuA25 (Optical Society of America, 2011), p. JTuA25 [Abstract] [PDF] [BibTeX]

    Abstract: Using femtosecond pump-probe thermal lens (TL) spectroscopy, we show that the effect of isotope substitution can be monitored through a modulation of TL signals in binary liquids showing the important of molecular properties on TL.

     BibTeX: @inproceedings{kumarThermalLensSpectroscopyBinary2012,
      langid = {english},
      title = {Thermal-{{Lens Spectroscopy}} in {{Binary Liquids Mixtures}}: {{Effect}} of {{Isotope Substitution}}},
      url = {https://www.osapublishing.org/abstract.cfm?uri=FiO-2011-JTuA25},
      doi = {10/gf5nqg},
      shorttitle = {Thermal-{{Lens Spectroscopy}} in {{Binary Liquids Mixtures}}},
      eventtitle = {Frontiers in {{Optics}}},
      booktitle = {Frontiers in {{Optics}} 2011/{{Laser Science XXVII}} (2011), Paper {{JTuA25}}},
      publisher = {{Optical Society of America}},
      urldate = {2019-08-02},
      date = {2011-10-16},
      pages = {JTuA25},
      author = {Kumar, Pardeep and Bhattacharyya, Indrajit and Goswami, Debabrata}
    }
    
  16. Effect of Molecular Structural Isomers in Thermal Lens Spectroscopy. P. Kumar, S. Dinda, and D. Goswami, Chemical Physics Letters 601, 163–167 (2014) [Abstract] [PDF] [BibTeX]

    Abstract: We explore the importance of molecular structure on thermal lens (TL) spectroscopy by measuring the effects of molecular isomerization on TL measurements. In particular, we present a case study for all the structural isomers of butanol, namely, normal-butanol (n-BuOH), secondary-butanol (s-BuOH), isobutanol (i-BuOH) and tertiary-butanol (t-BuOH). We argue that the molecular isomerization influences the heat convection process in two possible ways: one being a change in the molecular surface area and the other being the steric hindrance. We show that n-BuOH has the highest capability to transfer heat by convection. Branching in the molecular structure renders the system sluggish as it makes the molecular motion successively retarded due to an increase in the mean free path. This we have defined as the molecular drift that slows under thermal conditions. In our studied isomers, therefore, t-BuOH drifts the slowest.

     BibTeX: @article{kumarEffectMolecularStructural2015,
      langid = {english},
      title = {Effect of Molecular Structural Isomers in Thermal Lens Spectroscopy},
      volume = {601},
      issn = {00092614},
      url = {https://linkinghub.elsevier.com/retrieve/pii/S0009261414002620},
      doi = {10/gf6bk6},
      journaltitle = {Chemical Physics Letters},
      urldate = {2019-08-12},
      date = {2014-05},
      pages = {163-167},
      author = {Kumar, Pardeep and Dinda, Sirshendu and Goswami, Debabrata}
    }
    
  17. Probing Intermolecular Interaction through Thermal-Lens Spectroscopy. I. Bhattacharyya, P. Kumar, and D. Goswami, J. Phys. Chem. B 115(2), 262–268 (2011) [Abstract] [PDF] [BibTeX]

    Abstract: Binary liquid mixtures are studied using femtosecond pump−probe thermal-lens (TL) spectroscopy. Changes in the measured TL signals as a function of relative concentration of binary mixtures show that these result from a combined effect of physical and molecular properties of the constituent binary liquids. The experimental TL values deviate from the ones calculated from phenomenological equations. These, we argue, are due to an underestimation of the influence of molecular interactions when the TL signals are calculated by using physical parameters only.

     BibTeX: @article{bhattacharyyaProbingIntermolecularInteraction2012,
      title = {Probing {{Intermolecular Interaction}} through {{Thermal}}-{{Lens Spectroscopy}}},
      volume = {115},
      issn = {1520-6106},
      url = {https://doi.org/10.1021/jp1062429},
      doi = {10/d9mz5f},
      number = {2},
      journaltitle = {J. Phys. Chem. B},
      urldate = {2019-08-14},
      date = {2011-01-20},
      pages = {262-268},
      author = {Bhattacharyya, Indrajit and Kumar, Pardeep and Goswami, Debabrata}
    }
    
  18. Thermal-Lens Spectroscopy in Binary Liquids Mixtures. I. Bhattacharyya, P. Kumar, and D. Goswami, in Frontiers in Optics 2010/Laser Science XXVI (2010), Paper FWX1 (Optical Society of America, 2010), p. FWX1 [Abstract] [PDF] [BibTeX]

    Abstract: Using femtosecond pump-probe thermal-lens (TL) spectroscopy, experiments in binary-mixtures are presented where trends in TL are modulated by physical and molecular properties. Deviations of experimental results from phenomenological models indicate possible underestimation of molecular interactions.

     BibTeX: @inproceedings{bhattacharyyaThermalLensSpectroscopyBinary2011,
      langid = {english},
      title = {Thermal-{{Lens}} Spectroscopy in Binary Liquids Mixtures},
      url = {https://www.osapublishing.org/abstract.cfm?uri=FiO-2010-FWX1},
      doi = {10.1364/FIO.2010.FWX1},
      eventtitle = {Frontiers in {{Optics}}},
      booktitle = {Frontiers in {{Optics}} 2010/{{Laser Science XXVI}} (2010), Paper {{FWX1}}},
      publisher = {{Optical Society of America}},
      urldate = {2019-08-14},
      date = {2010-10-24},
      pages = {FWX1},
      author = {Bhattacharyya, Indrajit and Kumar, Pardeep and Goswami, Debabrata}
    }