Department of Physics
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Item Solvatochromic study of quinidine: Determination of ground and excited state dipole moments(AIP, 2013-06) Pant, Debi D.The absorption and fluorescence spectra of quinidine (QD) have been recorded at room temperature in wide range of solvents of different polarities. The absorption maximum remains almost unchanged with the increase in solvent polarity, whereas a red shift in fluorescence emission maximum was observed. Ground and excited state dipole moments of probe quinidine (QD) was obtained using Solvatochromic shift method. Higher dipole moment is observed for excited state as compared to the ground state which is attributed to the higher polarity of excited stateItem Estimation of ground and excited state dipole moments of 6-methoxyquinoline from solvatochromic effect on absorption and fluorescence spectra(AIP, 2013-06) Pant, Debi D.The electronic absorption and fluorescence spectra of 6-methoxyquinoline (6MQ) have been recorded at room temperature in solvents of different polarities. The spectral data have been used to evaluate the ground and first excited singlet state dipole moments using the solvatochromic shift method. Higher dipole moment is obtained for the excited state as compared to ground state. The results indicate a more polar excited state, which may be due to charge transfer character of 6MQ.Item Solvent effect on absorption and fluorescence spectra of cinchonine and cinchonidine dications: Estimation of ground and excited state dipole moments by experimental and numerical studies(Elsevier, 2015-06) Pant, Debi D.Absorption and fluorescence spectra of dications of cinchonine (C2 +) and cinchonidine (Cd2 +) have been measured at room temperature in solvents of different polarities. Ground and excited state electric dipole moments are determined experimentally using solvatochromic shift method based on bulk solvent properties. Theoretical calculations are done using B3LYP/6-31G(D) and CIS/6-31G(D) levels of theory for ground and excited states, respectively. Both experimental and theoretical studies reveal that excited state dipole moment (μe) values are higher than corresponding ground state dipole moment (μg) value of C2 + and Cd2 +, which is attributed to the higher polarity of excited states compared to the ground state polarity of these molecules.Item Solvatochromatic shift of absorption and fluorescence spectra of 6-methoxyquinoline: Estimation of ground and excited state dipole moments(Elsevier, 2013-03) Pant, Debi D.Electronic absorption and fluorescence spectra of protonated 6-methoxyquinoline (6MQ+) and neutral 6-methoxyquinoline (6MQ) have been recorded at room temperature in wide range of solvents of different polarities. The absorption maximum remains almost unchanged with the increase in solvent polarity, whereas a red shift in fluorescence emission maximum was observed. The ground-state dipole moment and the first excited singlet state dipole moment of 6MQ+ and 6MQ were obtained from Bakhshiev's and Bilot–Kawski's equations by means of solvatochromic shift method. High values of dipole moment are observed for excited state as compared to the corresponding ground state dipole moment values of 6MQ+ and 6MQ and this is attributed to the more polar excited states of 6MQ+ and 6MQ.Item Estimation of ground and excited state dipole moments of quinidine and quinidine dication: Experimental and numerical methods(Elsevier, 2013-03) Pant, Debi D.Absorption and fluorescence spectra of quinidine (QD) and quinidine dication (QD2 +) have been measured at room temperature in solvents of different polarities. Ground and excited state electric dipole moments are determined experimentally using solvatochromic shift method based on bulk solvent properties. Numerical calculations are also performed using B3LYP/6-31G(D) level of theory for ground state and CIS/6-31G(D) level of theory for first excited singlet state. From both experimental and numerical studies it has been observed that dipole moment values of excited states (μe) are higher than corresponding ground state value (μg), of QD and QD2 +, which is attributed to the higher polarity of excited states of QD and QD2 + molecules.Item Estimation of ground and excited state dipole moments of synthesized coumarin derivative [N-(2-oxo-2H-chromen-4-yl)imino]triphenyl-phosphorane(Elsevier, 2014-12) Pant, Debi D.Electronic absorption and fluorescence spectra of coumarin derivative [N-(2-oxo-2H-chromen-4-yl)imino] triphenyl phosphorane have been recorded at room temperature in wide range of solvents of different polarities. The absorption maximum remains almost unchanged with the increase in solvent polarity, whereas, a red shift in fluorescence emission maximum was observed. Synthesized compound [N-(2-oxo-2H-chromen-4-yl)imino] triphenyl phosphorane was characterized by 1H and 13C NMR, and FT-IR spectral studies. The ground and excited state dipole moments of molecule were obtained from Bakhshiev's and Bilot–Kawski's equations by means of the solvatochromic shift method. Very high value of dipole moment is observed for excited state as compared to ground state value and this is attributed to more polar excited state of the molecule. Numerical calculations are performed using B3LYP/6-31G+(d) and B3LYP/6-31G(d) level of theory for ground state in Gaussian 03. Studies in different solvents are also done using the CPCM method and UA0 radii with the same level of theory. A critical analysis between the values of dipole moment in gas phase and various solvents is also carried out for ground state.Item Solvatochromic shift and estimation of dipole moment of quinine sulfate(Elsevier, 2012-02) Pant, Debi D.The absorption and fluorescence spectra of quinine sulfate (QS) have been recorded at room temperature in wide range of solvents of different polarities. The ground-state dipole moment of QS was obtained from quantum mechanical calculations and the excited state dipole moment of QS was estimated from Bakhshiev's and Bilot–Kawski's equations by means of solvatochromic shift method. Higher value of dipole moment has been observed for excited state as compared to the corresponding ground state value and this is attributed to the more polar excited state of QS.Item Ground and excited state dipole moments of quinine sulfate dication: Solvatochromic shift of absorption and fluorescence spectra(Elsevier, 2012-08) Pant, Debi D.Electronic absorption and fluorescence spectra of quinine sulfate dication (QSD) have been recorded at room temperature in a wide range of solvents of different polarities. The absorption maximum remains almost unchanged with the increase in solvent polarity, whereas a red shift in fluorescence emission maximum was observed. The ground-state dipole moment of QSD was obtained from quantum mechanical calculations and the first excited singlet state dipole moment of QSD was obtained from Bakhshiev's and Bilot–Kawski's equations by means of solvatochromic shift method. Very high value of dipole moment is observed for excited state as compared to the corresponding ground state value and this is attributed to the more polar excited state of QSD. Compared to the dipole moment of quinine sulfate, both the ground and excited state dipole moments of QSD are lower.