Summary Theoretical Study on Short-Chain Fatty Acids arxiv.org
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Theoretical studies on short-chain fatty acids were conducted, evaluating computational methods for calculating their properties and providing insights into their behavior and potential applications in molecular spectroscopy and the origin of life.
Key Points
- Short-chain fatty acids (SCFAs) are significant precursor molecules of carbon-based life and play a pivotal role in the origin of life.
- SCFAs have been widely observed in space through their microwave rotational spectrum and have been found in meteorites.
- The stability and vibration characteristics of SCFA clusters were analyzed, and the type of rotational spectra was determined.
- The revDSD-PBEP86-D3(BJ) method with the may-cc-pVTZ basis set was found to be the most suitable for calculating rotational constants for SCFAs and their hydrates.
- The study found that internal rotations can occur at low temperatures, but higher temperatures may lead to changes in cluster structure and a decline in stability.
Summaries
282 word summary
A theoretical study on short-chain fatty acids was conducted, analyzing their energy under varying temperatures. Twelve different methods were used to calculate rotational constants, centrifugal distortion constants, dipole moment, and RMSDs of SCFAs geometries. MP2 and ?B97X-D were found to be outstanding in calculating geometric structures. The study found that internal rotations can occur at low temperatures, but higher temperatures may lead to changes in cluster structure and a decline in stability. The study also identified intramolecular interactions and provides theoretical support for the behavior of SCFAs. Other studies aim to improve calculations of molecular properties, thermochemistry, kinetics, and noncovalent interactions. A theoretical study was conducted to evaluate computational methods for calculating rotational constants for short-chain fatty acids (SCFAs) and their hydrates. The revDSD-PBEP86-D3(BJ) method with the may-cc-pVTZ basis set was deemed the most suitable. The study investigated the rotational transitions of Ac, Ac-w, and Ac-w2 and found that they may not have c-type spectra. The stability of two types of SCFA hydrates in the presence of water was investigated, and it was found that SCFAs in outer space preferentially form more stable dihydrate clusters. The study provides useful insights into the properties of SCFAs.
Theoretical studies on SCFAs were conducted using various computational methods, including AIMD and high order symmetry-adapted perturbation theory (SAPT). The results provide new insights for the development of molecular spectroscopy and its application in the chemistry field.
SCFAs are significant precursor molecules of carbon-based life and play a pivotal role in the origin of life. The study confirms that the internal rotations of SCFAs could be observed under low-temperature and low-pressure conditions. SCFAs hydrate clusters may exist in the form of monohydrates and dihydrates in interstellar space.
765 word summary
Short-chain fatty acids (SCFAs) are significant precursor molecules of carbon-based life and play a pivotal role in the origin of life. They have been widely observed in space through their microwave rotational spectrum and have been found in meteorites. The study investigates whether the internal rotations of SCFAs could be observed and confirms their existence under low-temperature and low-pressure conditions. SCFAs are important in physiological and biochemical processes, forming biological membranes. The study suggests that SCFAs hydrate clusters may exist in the form of monohydrates and dihydrates in interstellar space.
Theoretical studies on SCFAs were conducted using various computational methods, including AIMD and high order symmetry-adapted perturbation theory (SAPT). Structural models of different SCFAs and their mono- and dihydrates were constructed and optimized using different basis sets and functionals. The stability and vibration characteristics of the clusters were analyzed, and the type of rotational spectra was determined by calculating the resonant frequency of the vibration-rotation coupling. The internal rotation and cluster stability were simultaneously studied using ab initio molecular dynamics (AIMD) innovatively at different temperatures. The results provide new insights for the development of molecular spectroscopy and its application in the chemistry field. This theoretical study evaluated various computational methods for calculating rotational constants for short-chain fatty acids (SCFAs) and their hydrates. The revDSD-PBEP86-D3(BJ) method with the may-cc-pVTZ basis set was found to be the most suitable. The study investigated the rotational transitions of Ac, Ac-w, and Ac-w2 and found that they may not have c-type spectra. The stability of two types of SCFA hydrates in the presence of water was investigated, and it was found that SCFAs in outer space preferentially form more stable dihydrate clusters. Electrostatic attraction dominates the energy decomposition calculation for hydrated clusters, while dispersion and induction play an auxiliary role. Four water-maintained cluster morphologies were constructed to maintain stability at low temperature and pressure. The rev-DSD-PBEP86-D3(BJ) method was found to be superior to the combined method of rev-DSD-PBEP86-D3(BJ) in terms of calculating electronic structure, electron density, dipole moment, rotational constants, and thermodynamic energy. The CCSD(T) method is more accurate than rev-DSD-PBEP86-D3(BJ) in calculating electronic energy but cannot obtain information such as free energy correction quantities without the Hessian matrix for vibrational analysis. The MP2 method requires three days and six hours, making it less cost-effective. Overall, the study provides useful insights into the properties of SCFAs. This is a theoretical study on short-chain fatty acids, examining their stability and behavior under different conditions. The study found that internal rotations can occur at low temperatures, but higher temperatures may lead to changes in cluster structure and a decline in stability. The study also identified intramolecular interactions and provides theoretical support for the behavior of SCFAs. Previous studies have explored the potential health benefits of SCFAs and conducted rotational studies on various molecules. Additionally, other studies aim to improve calculations of molecular properties, thermochemistry, kinetics, and noncovalent interactions. This document presents a theoretical study on short-chain fatty acids (SCFAs) and their corresponding water clusters. Twelve different methods were used to calculate rotational constants, centrifugal distortion constants, dipole moment, and RMSDs of SCFAs geometries. MP2 and ?B97X-D were found to be outstanding in calculating geometric structures, while the rest of the ordinary functionals were not as good. The coordinates of the optimized geometries calculated with different methods were summarized, and the optimal rev-DSDPBEP86-D3(BJ) was used as the benchmark. The study calculated the rotational constants, centrifugal distortion constants, and dipole moment of AA-w, PPA-w 2, BA, BA-w, PTA, HXA-w, HXA, and PTA-w2 using twelve different methods. The results show variations in the calculated parameters depending on the method used. Three separate tables present the calculated parameters for PPA, PPA-w 2, BA, BA-w, PTA, HXA-w, HXA, and PTA-w2. The values for I, J, K, and the dipole moment are listed for each method used. A theoretical study on short-chain fatty acids evaluated twelve different methods for calculating rotational constants and determined the optimal method through benchmark data. The study also lists parameters calculated with different methods for various short-chain fatty acids.
The document presents a theoretical study on short-chain fatty acids, analyzing the energy of different substances under varying temperatures. The study includes tables with data on electrostatics, exchange, induction, dispersion, and total SAPT2+(3) ?MP2 energy, as well as slopes and intercepts for different substances.
The study includes dihedral angle changes in HXA-w, PTA-w, BA-w, and AA-w molecules at different temperatures. The dihedral angle of the most stable structure is 58.01?, and it varies from 54.03? to 61.90?. The ?G of the water-losing process is also presented at different temperatures ranging from 5K to 350K.
2079 word summary
This document presents a theoretical study on short-chain fatty acids. The study includes dihedral angle changes in HXA-w, PTA-w, BA-w, and AA-w molecules at different temperatures. The dihedral angle of the most stable structure is 58.01?, and it varies from 54.03? to 61.90?. The ?G of the water-losing process is also presented at different temperatures ranging from 5K to 350K. This document presents a theoretical study on short-chain fatty acids, analyzing the energy of different substances under varying temperatures. The results show strong linear correlation, with smaller error as the main dominance and the intercept close to 0 as the auxiliary reference. The study also includes tables with data on electrostatics, exchange, induction, dispersion, and total SAPT2+(3) ?MP2 energy, as well as slopes and intercepts for different substances. A theoretical study on short-chain fatty acids evaluated twelve different methods for calculating rotational constants and determined the optimal method through benchmark data. Table S3 shows the systematic error of calculating rotational constants using twelve different methods. Figure S1 and Figure S2 display the absolute errors for rotational constants C and B of various short-chain fatty acids calculated using these methods. Table S2.14 provides rotational constants, centrifugal distortion constants, and dipole moment of HXA-w 2 calculated with twelve different methods. The study also lists parameters calculated with different methods for various short-chain fatty acids. This document presents a theoretical study on short-chain fatty acids. Twelve different methods were used to calculate the rotational constants, centrifugal distortion constants, and dipole moments of HXA-w, HXA, and PTA-w2. The results show variations in the values obtained depending on the method used for calculation. The document presents a theoretical study on short-chain fatty acids. Table S2.10 shows the rotational constants, centrifugal distortion constants, and dipole moment of PTA calculated with twelve different methods. Table S2.9 shows the same parameters for BA-w 2. Both tables include values for I? TOT I, I? b I, I? c I, and I? a I in units of D, as well as values for ? K (kHz), ? J (kHz), ? JK (kHz), ? K (kHz), ? J (kHz), C (MHz), B (MHz), and A (MHz). Theoretical calculations were performed on the short-chain fatty acids BA and BA-w using twelve different methods. Table S2.7 and S2.8 display the rotational constants, centrifugal distortion constants, and dipole moment for both molecules. The values for I, J, K, and the dipole moment are listed for each method used. This document presents a theoretical study of short-chain fatty acids. Twelve different methods were used to calculate the rotational constants, centrifugal distortion constants, and dipole moment of PPA-w 2. The results are presented in three separate tables (S2.4, S2.5, S2.6). The first table presents the calculated parameters for PPA, while the second and third tables present the parameters for PPA-w 2. The results show variations in the calculated parameters depending on the method used. This document presents a theoretical study on short-chain fatty acids. The study calculated the rotational constants, centrifugal distortion constants, and dipole moment of AA-w using twelve different methods. The calculated values for I? TOT I (D) ranged from 1.32 to 2.34, for I? c I (D) from 1.22 to 2.31, for I? b I (D) from 0.00 to 0.10, and for I? a I (D) from 0.19 to 0.61. The values for ? K (kHz) ranged from 597.491 to 5386.752, for ? J (kHz) from 0.0788 to 299.265, for ? JK (kHz) from 2076.996 to 5755.144, and for A (MHz) from 4236.2670 to 4584.6877. The values for C (MHz) ranged from 1145.8735 to 1245.4942, and for B (MHz) from 1531.0366 to 1681.1677. This document presents a theoretical study on short-chain fatty acids (SCFAs) and their corresponding water clusters. Twelve different methods were used to calculate rotational constants, centrifugal distortion constants, dipole moment, and RMSDs of SCFAs geometries. MP2 and ?B97X-D were found to be outstanding in calculating geometric structures, while the rest of the ordinary functionals were not as good. However, despite being mediocre in calculating the rotational constants of SCFAs, MP2 and ?B97X-D methods are plausible. The coordinates of the optimized geometries calculated with different methods were summarized, and the optimal rev-DSDPBEP86-D3(BJ) was used as the benchmark. This text excerpt contains statistical measures for a set of calculated data compared to experimental reference data. The supporting information includes a list of references related to the study of short-chain fatty acids, including studies on the conformation of polypeptides and proteins, hydrogen bonding in hydrates, and microwave spectroscopy. The references also cover topics such as molecular thermochemistry properties, Gaussian basis sets for correlated molecular calculations, and electron affinities of first-row atoms. This text excerpt lists various studies and theories related to intermolecular forces and quantum chemistry. The studies include perturbation theory, Gaussian basis sets, density functional methods, and double-hybrid functionals, among others. The studies aim to improve calculations of molecular properties, thermochemistry, kinetics, and noncovalent interactions. They also involve testing new functionals and assessing the accuracy of different methods. Theoretical studies on short-chain fatty acids have been conducted using density functional theory with various exchange-correlation functionals. Short-chain fatty acids have potential health benefits, including regulating body weight and insulin sensitivity. Prebiotic amino acids have been found to bind and stabilize prebiotic fatty acid membranes. Rotational studies have been conducted on acetic acid and fluoroacetic acid bimolecules, as well as the propylene oxide-water adduct. High-resolution microwave spectroscopy and ab initio studies have been conducted on propanoic acid and its hydrates. This excerpt is a reference list and conclusion from a theoretical study on short-chain fatty acids (SCFAs). The study used computational methods to analyze the structure and behavior of SCFAs, including their ability to rotate and form hydrated clusters. The optimal calculation method was determined to be PBEP86-D3(BJ), with excellent spectroscopic parameters. The study found that the presence of a methylene group hinders the rotation of the terminal methyl group. The study also identified intramolecular interactions between H atoms and O or H atoms, with van der Waals interaction present in some cases. Overall, the study provides theoretical support for the behavior of SCFAs in different conditions. This is a theoretical study on short-chain fatty acids. The study investigates the internal rotation of the methyl group in AA-w and BA-w at different temperatures using microwave rotational spectra and AIMD simulations. The distance r(H...O) of radius of H, O atoms are 1.0 A and 1.35 A, the minimum distance that atoms in can interact with each structure of AA-w and BA-w for the difference of the rotation of ? in Fig.8. The study found that only AA-w can rotate at high temperature, while BA-w only performs small-scale thermal fluctuations in stable conformational space and there is no internal rotation at 5 K. The dihedral angle of terminal -CH3 is mainly investigated. According to the results, internal rotations can occur at the temperatures of 5 K, 50 K, and 100 K. This theoretical study examines the stability and dynamic behavior of short-chain fatty acid (SCFA) clusters. Molecular dynamics simulations were used to verify the stability of the clusters with even numbers of carbons. The study selected moderate SCFA monohydrates for AIMD simulations at different temperatures. The study explored the relationship between internal rotation and temperature, locating the rotational transition state and adding thermo corrections to the acids and clusters at 5 K, 50 K, 100 K, and 298 K. The study found that internal rotations for SCFAs and clusters containing three carbons and more have relatively high barriers, making them stable and unable to occur. The study also found that higher temperatures may lead to changes in the cluster skeleton and a decline in stability. The Gibbs free energies of the dehydration procedure of water monomer and water dimer were calculated at different temperatures. A theoretical study was conducted on short-chain fatty acids (SCFAs) using SAPT to compute electronic energy without thermal corrections. The stability of two types of hydrates of SCFAs in the presence of water was investigated. It was found that SCFAs in outer space preferentially form more stable dihydrate clusters. Water restricts the rotation of the acid, and the dimer requires more energy to lose two water molecules, making it more stable. Electrostatic attraction dominates the energy decomposition calculation for hydrated clusters, while dispersion and induction play an auxiliary role. Four water-maintained cluster morphologies were constructed to maintain stability at low temperature and pressure. The combined method of rev-DSD-PBEP86-D3(BJ) is inferior to the rev-DSD-PBEP86-D3(BJ) method in terms of calculating electronic structure, electron density, dipole moment, rotational constants, and thermodynamic energy. Although the CCSD(T) method is more accurate than rev-DSD-PBEP86-D3(BJ) in calculating electronic energy, it cannot obtain information such as free energy correction quantities without the Hessian matrix for vibrational analysis. The MP2 method requires three days and six hours, making it less cost-effective. This theoretical study on short-chain fatty acids (SCFAs) evaluated the performance of various computational methods in calculating rotational constants for SCFAs and their hydrates. The revDSD-PBEP86-D3(BJ) method with the may-cc-pVTZ basis set was found to be the most suitable for the calculation. The study also noted that dipole moment calculations were important for predicting rotational spectra, and the revDSD-PBEP86-D3(BJ) method was suitable for calculating electron structures and dipole moments. The study investigated the rotational transitions of Ac, Ac-w, and Ac-w2, and found that they may not have c-type spectra due to their nearly symmetric planar structure. This study presents optimized structures and microwave rotational constants for short-chain fatty acids using twelve different computational methods. The results are summarized in Table 2 and Tables S2.1-2.14 of the supporting information. The structures were optimized at the revDSD-PBEP86-D3(BJ)/may-cc-pVTZ level and were found to be reliable based on the RMSD values provided in Table S1 of the supporting information. The study also includes initial structures for AA hydrates and predicts high resolution microwave rotational spectra for gaseous molecules in isolated systems under vacuum. The calculated results are reasonable and reliable, and the study provides useful insights into the properties of short-chain fatty acids. A theoretical study on short-chain fatty acids (SCFAs) was conducted using various computational methods, including AIMD and high order symmetry-adapted perturbation theory (SAPT). Structural models of AA, PPA, BA, PTA, HXA and their mono- and dihydrates were constructed and optimized using different basis sets and functionals. The stability and vibration characteristics of the clusters were analyzed, and the type of rotational spectra was determined by calculating the resonant frequency of the vibration-rotation coupling. The suitable calculation method for such a system was confirmed after being compared with existing experimental results. The internal rotation and cluster stability were simultaneously studied using ab initio molecular dynamics (AIMD) innovatively at different temperatures. The composition of dissociation energy (?G) was studied, and the free energy barrier (?G != ) of internal rotations can be obtained. These results provide new insights for the development of molecular spectroscopy and its application in the chemistry field. This study focuses on the simulation of straight short-chain fatty acids (SCFAs) and their hydrate clusters. The study uses ab initio and DFT methods to calculate various properties of SCFAs, including geometric structures, rotational constants, and collision and combination probabilities. The study also investigates internal rotation issues and the role of hydrogen bonding between organic acids. The microwave rotational spectra of small molecules are used to obtain information such as molecular structure, spectroscopic constants, and binding energy. SCFAs play an important role in physiological and biochemical processes, forming biological membranes by combining with glycerol and phosphoric acid to form phospholipids. Additionally, the study suggests that SCFAs hydrate clusters may exist in the form of monohydrates and dihydrates in interstellar space. Short-chain fatty acids (SCFAs) are precursor molecules of life and are the basis for the existence of carbon-based life. They have significant biological significance and play a pivotal role in the origin of life. SCFAs are widely observed in space by assistance of their microwave rotational spectrum and have also been found in meteorites. The abundance of molecules can be reflected by the strength of spectra, thus indicating the temperature of the environment. Microwave Rotational Spectra are used to not only diagnose the physical state of molecules in circumstellar nebulae and envelopes but also confirm the molecules in interstellar space. Several short-chain fatty acids and their corresponding potential existing hydrated forms are important molecules in interstellar space. The study investigates whether the internal rotations of acids could be observed and confirms their existence under low-temperature and low-pressure conditions. The most suitable method selected for rotational calculation is the benchmark study revDSD-PBEP86-D3(BJ).