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Papers by Charles Bauschlicher

Research paper thumbnail of The A 6Σ+-X 6Σ+ transition of CrH, Einstein coefficients, and an improved description of the A state

The Journal of Chemical Physics, 2001

The spectrum of CrH has been reinvestigated in the 9000–15 000 cm−1 region using the Fourier tran... more The spectrum of CrH has been reinvestigated in the 9000–15 000 cm−1 region using the Fourier transform spectrometer of the National Solar Observatory. The 1-0 and 1-1 bands of the A 6Σ+-X 6Σ+ transition have been measured and improved spectroscopic constants have been determined. A value for the 2-0 band origin has been obtained from the band head using estimated spectroscopic constants. These data provide a set of much improved equilibrium vibrational and rotational constants for the A 6Σ+ state. An accurate description of the A-X transition has been obtained using a multireference configuration interaction approach. The inclusion of both scalar relativity and Cr 3s3p correlation are required to obtain a good description of both states. The ab initio computed Einstein coefficients and radiative lifetimes are reported.

Research paper thumbnail of Transverse polarizabilities of carbon nanotubes: A Hartree-Fock and density functional study

Physical Review B, 2005

The transverse polarizabilities of carbon nanotubes are computed using Hartree-Fock ͑HF͒ and dens... more The transverse polarizabilities of carbon nanotubes are computed using Hartree-Fock ͑HF͒ and density functional theory ͑DFT͒. The results of these calculations have implications for nanoelectronics, specifically for the possibility of using nanotubes as shielding for nanoelectrical components, as the results do not support the proposed enhanced polarizability, and hence enhanced shielding, of nanotubes based on metallicity. The HF and DFT calculations are shown to be in close agreement, and this agreement is discussed. We find the polarizability per unit length depends on the square of the tube radius, and is not dependent on metallicity. The current calculations are consistent with tight binding calculations using four orbitals per carbon with regard to both trend and magnitude, but differ from some recent tight binding calculations performed using one orbital per carbon. The calculations detailed in this paper are the most elaborate to date, and settle contradictory reports in the literature.

Research paper thumbnail of Functionalization of Carbon Nanotubes by Ammonia Glow-Discharge:  Experiments and Modeling

The Journal of Physical Chemistry B, 2004

We successfully functionalized single-walled carbon nanotubes (SWNTs) through a microwave dischar... more We successfully functionalized single-walled carbon nanotubes (SWNTs) through a microwave discharge of ammonia. Evidence is supplied through Fourier transform infrared (FTIR) spectroscopy with band assignment aided by computational modeling. X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy results also provide supporting evidence of functional groups attached to the surfaces of SWNTs from ammonia plasma.

Research paper thumbnail of The A 6Σ+-X 6Σ+ transition of CrH, Einstein coefficients, and an improved description of the A state

The Journal of Chemical Physics, 2001

The spectrum of CrH has been reinvestigated in the 9000–15 000 cm−1 region using the Fourier tran... more The spectrum of CrH has been reinvestigated in the 9000–15 000 cm−1 region using the Fourier transform spectrometer of the National Solar Observatory. The 1-0 and 1-1 bands of the A 6Σ+-X 6Σ+ transition have been measured and improved spectroscopic constants have been determined. A value for the 2-0 band origin has been obtained from the band head using estimated spectroscopic constants. These data provide a set of much improved equilibrium vibrational and rotational constants for the A 6Σ+ state. An accurate description of the A-X transition has been obtained using a multireference configuration interaction approach. The inclusion of both scalar relativity and Cr 3s3p correlation are required to obtain a good description of both states. The ab initio computed Einstein coefficients and radiative lifetimes are reported.

Research paper thumbnail of Transverse polarizabilities of carbon nanotubes: A Hartree-Fock and density functional study

Physical Review B, 2005

The transverse polarizabilities of carbon nanotubes are computed using Hartree-Fock ͑HF͒ and dens... more The transverse polarizabilities of carbon nanotubes are computed using Hartree-Fock ͑HF͒ and density functional theory ͑DFT͒. The results of these calculations have implications for nanoelectronics, specifically for the possibility of using nanotubes as shielding for nanoelectrical components, as the results do not support the proposed enhanced polarizability, and hence enhanced shielding, of nanotubes based on metallicity. The HF and DFT calculations are shown to be in close agreement, and this agreement is discussed. We find the polarizability per unit length depends on the square of the tube radius, and is not dependent on metallicity. The current calculations are consistent with tight binding calculations using four orbitals per carbon with regard to both trend and magnitude, but differ from some recent tight binding calculations performed using one orbital per carbon. The calculations detailed in this paper are the most elaborate to date, and settle contradictory reports in the literature.

Research paper thumbnail of Functionalization of Carbon Nanotubes by Ammonia Glow-Discharge:  Experiments and Modeling

The Journal of Physical Chemistry B, 2004

We successfully functionalized single-walled carbon nanotubes (SWNTs) through a microwave dischar... more We successfully functionalized single-walled carbon nanotubes (SWNTs) through a microwave discharge of ammonia. Evidence is supplied through Fourier transform infrared (FTIR) spectroscopy with band assignment aided by computational modeling. X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy results also provide supporting evidence of functional groups attached to the surfaces of SWNTs from ammonia plasma.

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