Time Dependent DFT (TD-DFT) Calculations for Raman and Optical Spectroscopy

Ronald Birke, CUNY The City College of New York

0000-0001-8162-9254

ACCESS Allocation Request CHE080076

Abstract:

Our quantum chemistry computational effort is directed toward two specific areas: A. Determining the structure of test molecules and molecular aggregates on the surfaces of metal and semiconductor nanoparticles in order to obtain optical spectra and vibrational spectra which simulate Surface Enhanced Raman Scattering (SERS) spectroscopy. B. Determining the geometry and optical and vibrational spectra in solution and/or on solids for molecules of practical importance such as drug opiates, pigments used in art preservation, and dyes which form J-aggregates. We will calculate Raman intensities and optical spectra by DFT and time-dependent density functional theory (TD-DFT) for molecules bound to surfaces. These calculations will help explain the differences in spectra for a given molecular compound as observed in normal Raman (NR), resonance Raman (RR) , and in the SERS from metal and semiconductor nanoparticle systems. We will continue our work on II-VI low band gap Zn or Pb chacologenides with adsorbed 4-mercaptopyridine. Also, we will study the wide band gap semiconductors TiO2 and ZnO with slab and/or nanocluster models with adsorbed solar cell dyes such as N3 and N719. Other systems for spectroscopy investigation with TD-DFT are the optical excitation properties of the MnO4(2)- and MnO4(3)- anions found in the pigment Manganese Blue, Raman and optical simulation of fentanyl analogs and cannabinoid drugs, and the optical properties found for cyanine dyes in various forms from monomers to J-aggregates.

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Allocations:

2022	SDSC Expanse CPU	76,000.0 Core-hours
2022	SDSC Expanse GPU	9,390.0 GPU Hours
2022	SDSC Expanse Projects Storage	600.0 GB
The estimated value of these awarded resources is $6,467.90. The allocation of these resources represents a considerable investment by the NSF in advanced computing infrastructure for the U.S. The dollar value of the allocation is estimated from the NSF awards supporting the allocated resources.
2021	SDSC Expanse CPU	30,000.0 Core-hours
2021	SDSC Expanse GPU	10,000.0 GPU Hours
2021	SDSC Expanse Projects Storage	600.0 GB
The estimated value of these awarded resources is $6,662.00. The allocation of these resources represents a considerable investment by the NSF in advanced computing infrastructure for the U.S. The dollar value of the allocation is estimated from the NSF awards supporting the allocated resources.

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