Ground and asymmetric CO-stretch excited state tunneling splittings in the formic acid dimer

2007 ◽  
Vol 127 (1) ◽  
pp. 014309 ◽  
Author(s):  
I. Matanović ◽  
N. Došlić ◽  
O. Kühn
Keyword(s):  
Excited State ◽  
Formic Acid ◽  
Tunneling Splittings

scholarly journals Simplistic calculation of the tunneling splittings for proton transfer in malonaldehyde and formic acid dimer using the one-dimensional Schrödinger equation

2021 ◽  
Author(s):  
Denis S. Tikhonov
Keyword(s):  
Schrödinger Equation ◽  
Proton Transfer ◽  
Formic Acid ◽  
Schrodinger Equation ◽  
Zero Point ◽  
Basis Set ◽  
One Dimensional ◽  
Hartree Fock ◽  
Tunneling Splittings ◽  
Complete Basis Set

Abstract In this manuscript we present an approach for computing tunneling splittings for large amplitude motions. The core of the approach is a solution of an effective one-dimensional Schrödinger equation with an effective mass and an effective potential energy surface composed of electronic and harmonic zero-point vibrational energies of small amplitude motions in the molecule. The method has been shown to work in cases of three model motions: nitrogen inversion in ammonia, single proton transfer in malonaldehyde, and double proton transfer in the formic acid dimer. In the current work we also investigate the performance of different DFT and post-Hartree-Fock methods for prediction of the proton transfer tunneling splittings, quality of the effective Schrödinger equation parameters upon the isotopic substitution, and possibility of a complete basis set (CBS) extrapolation for the resulting tunneling splittings.

The effects of asymmetric motions on the tunneling splittings in formic acid dimer

2008 ◽  
Vol 129 (16) ◽  
pp. 164317 ◽  
Author(s):  
George L. Barnes ◽  
Edwin L. Sibert
Keyword(s):  
Formic Acid ◽  
Tunneling Splittings

X-RAY ABSORPTION SPECTRA OF SOME SMALL POLYATOMIC MOLECULES

2002 ◽  
Vol 09 (01) ◽  
pp. 159-164 ◽  
Author(s):  
K. C. PRINCE ◽  
R. RICHTER ◽  
M. DE SIMONE ◽  
M. CORENO
Keyword(s):  
Fine Structure ◽  
Excited State ◽  
High Resolution ◽  
Formic Acid ◽  
Absorption Spectra ◽  
Organic Molecules ◽  
Polyatomic Molecules ◽  
X Ray ◽  
Vibrational Progression ◽  
X Ray Absorption

We report the Near Edge X-ray Absorption Fine Structure Spectra (NEXAFS) of a series of oxygen-containing organic molecules, namely formaldehyde, acetaldehyde, acetone, formic acid, methanol and dimethyl ether (DME), measured with high resolution at the carbon and oxygen edges. A vibrational progression has been observed at the oxygen 1s → π* resonance of formaldehyde, indicating that this state is bound with an excited state C=O stretching frequency of 136 meV. The spectra are compared with previous measurements and the applicability of the chromophore concept is tested for the functional groups present in these molecules.

scholarly journals Accurate Tunneling Splittings for Proton Transfer in Malonaldehyde and Formic Acid Dimer Using the One-Dimensional Schrödinger Equation

2021 ◽  
Author(s):  
Denis Tikhonov
Keyword(s):  
Schrödinger Equation ◽  
Proton Transfer ◽  
Formic Acid ◽  
Schrodinger Equation ◽  
Zero Point ◽  
Basis Set ◽  
One Dimensional ◽  
Hartree Fock ◽  
Tunneling Splittings ◽  
Complete Basis Set

In this manuscript we present an approach for computing tunneling splittings for large amplitude motions. <br>The core of the approach is a solution of an effective one-dimensional Schrödinger equation with an effective mass and an effective potential energy surface composed of electronic and harmonic zero-point vibrational energies of small amplitude motions in the molecule.<br>The method has been shown to work in cases of three model motions: nitrogen inversion in ammonia, single proton transfer in malonaldehyde, and double proton transfer in the formic acid dimer. In the current work we also investigate the performance of different DFT and post-Hartree-Fock methods for prediction of the proton transfer tunneling splittings, quality of the effective Schrödinger equation parameters upon the isotopic substitution, and possibility of a complete basis set (CBS) extrapolation for the resulting tunneling splittings.<br>

scholarly journals Accurate Tunneling Splittings for Proton Transfer in Malonaldehyde and Formic Acid Dimer Using the One-Dimensional Schrödinger Equation

2021 ◽  
Author(s):  
Denis Tikhonov
Keyword(s):  
Schrödinger Equation ◽  
Proton Transfer ◽  
Formic Acid ◽  
Schrodinger Equation ◽  
Zero Point ◽  
Basis Set ◽  
One Dimensional ◽  
Hartree Fock ◽  
Tunneling Splittings ◽  
Complete Basis Set

In this manuscript we present an approach for computing tunneling splittings for large amplitude motions. <br>The core of the approach is a solution of an effective one-dimensional Schrödinger equation with an effective mass and an effective potential energy surface composed of electronic and harmonic zero-point vibrational energies of small amplitude motions in the molecule.<br>The method has been shown to work in cases of three model motions: nitrogen inversion in ammonia, single proton transfer in malonaldehyde, and double proton transfer in the formic acid dimer. In the current work we also investigate the performance of different DFT and post-Hartree-Fock methods for prediction of the proton transfer tunneling splittings, quality of the effective Schrödinger equation parameters upon the isotopic substitution, and possibility of a complete basis set (CBS) extrapolation for the resulting tunneling splittings.<br>

Analytical Gradients for Core-Excited States in the Algebraic Diagrammatic Construction (ADC) Framework

2021 ◽  
Author(s):  
Iulia Emilia Brumboiu ◽  
Dirk R. Rehn ◽  
Andreas Dreuw ◽  
Young Min Rhee ◽  
Patrick Norman
Keyword(s):  
Excited State ◽  
Potential Energy ◽  
Formic Acid ◽  
Excited States ◽  
Potential Energy Surfaces ◽  
The Core ◽  
Energy Surfaces ◽  
Analytical Expressions ◽  
Analytical Gradients ◽  
Optimized Geometries

Here we present a derivation of the analytical expressions required to determine nuclear gradients for core-excited states at the core-valence separated algebraic diagrammatic construction (CVS-ADC) theory level. Analytical gradients up to and including the extended CVS-ADC(2)-x order have been derived and implemented into a Python module, adc_gradient. The gradients were used to determine core-excited state optimized geometries and relaxed potential energy surfaces for the water, formic acid, and benzne molecules. <br>

Analytical Gradients for Core-Excited States in the Algebraic Diagrammatic Construction (ADC) Framework

2021 ◽  
Author(s):  
Iulia Emilia Brumboiu ◽  
Dirk R. Rehn ◽  
Andreas Dreuw ◽  
Young Min Rhee ◽  
Patrick Norman
Keyword(s):  
Excited State ◽  
Potential Energy ◽  
Formic Acid ◽  
Excited States ◽  
Potential Energy Surfaces ◽  
The Core ◽  
Energy Surfaces ◽  
Analytical Expressions ◽  
Analytical Gradients ◽  
Optimized Geometries

Here we present a derivation of the analytical expressions required to determine nuclear gradients for core-excited states at the core-valence separated algebraic diagrammatic construction (CVS-ADC) theory level. Analytical gradients up to and including the extended CVS-ADC(2)-x order have been derived and implemented into a Python module, adc_gradient. The gradients were used to determine core-excited state optimized geometries and relaxed potential energy surfaces for the water, formic acid, and benzne molecules. <br>

scholarly journals Simplistic calculation of the tunneling splittings for proton transfer in malonaldehyde and formic acid dimer using the one-dimensional Schrödinger equation

2021 ◽  
Author(s):  
Denis Tikhonov
Keyword(s):  
Schrödinger Equation ◽  
Proton Transfer ◽  
Formic Acid ◽  
Schrodinger Equation ◽  
Zero Point ◽  
Basis Set ◽  
One Dimensional ◽  
Hartree Fock ◽  
Tunneling Splittings ◽  
Complete Basis Set

In this manuscript we present an approach for computing tunneling splittings for large amplitude motions. <br>The core of the approach is a solution of an effective one-dimensional Schrödinger equation with an effective mass and an effective potential energy surface composed of electronic and harmonic zero-point vibrational energies of small amplitude motions in the molecule.<br>The method has been shown to work in cases of three model motions: nitrogen inversion in ammonia, single proton transfer in malonaldehyde, and double proton transfer in the formic acid dimer. In the current work we also investigate the performance of different DFT and post-Hartree-Fock methods for prediction of the proton transfer tunneling splittings, quality of the effective Schrödinger equation parameters upon the isotopic substitution, and possibility of a complete basis set (CBS) extrapolation for the resulting tunneling splittings.<br>

Sign in / Sign up

Export Citation Format

Share Document