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Questions related from Keshav Singh
I am new to the tinker molecular dynamics software. I want to use it for conformation analysis for organic molecules (say penta-alanine). This can be done by SCAN keyword. There manual does not...
01 April 2024 9,311 0 View
I want to calculate PECD spectra and in order to do so I require calculated electron density in terms of symmetry adopted spherical harmonic basis functions. How should I do that?
31 January 2023 695 3 View
I want to calculate photoelectron circular dichroism (PECD) using DFT and one approach (B-spline LCAO density functional theory (DFT))is to modify the current basis set by adding B-spline...
23 January 2023 10,043 0 View
is it possible to calculate photoelectron Circular dichroism (PECD) using quantum chemistry?
10 January 2023 1,704 4 View
I am trying to optimize the unit cell of caffeine using crystal 17. However, I am contently having the following error :- input (caffeine_opt2.d12) and output (caffeine_opt2.out)...
19 April 2022 585 0 View
I am trying to optimize a molecular crystal using CRYSTAL17 software. I am getting error that the basis set I am using is linearly dependent. How can I solve such issue. I tried changing my basis...
09 March 2022 7,016 6 View
I am trying to run USPEX with LAMMPS (example 4, in USPEX examples). However, when I try to run USPEX, I always get following error lmp_stable:...
24 August 2021 3,966 1 View
I am new to the quantum espresso and LAMMPS program. I wish to make nanocluster of Bismuth. Is it possible generate a structure of Bismuth nanocluster using either quantum espresso or LAMMPS? If...
11 August 2021 9,503 7 View
I am new to the solid state ab-initio calculations. I need to optimize the unit cell of paracetamol. For this, I required Fractional coordinates for the system. When I extract fractional...
22 March 2021 7,409 2 View
My question is why I am getting a charged cell at all even if the cif file is neutral. however, when I make input file using cif file of paracetamol (image and source file attached), it always...
02 March 2021 4,488 2 View
A cif file represents a unit cell with minimum energy. My question is, in the start of any ab initio calculation for unit cell generated from the cif file, why we are advised to optimize cell...
20 January 2021 10,401 3 View
I am using crystal 17 for my solid state ab initio calculations. For some reason the program is not able to produce the Raman spectra but have generated born charges. Is there any way to produce...
12 January 2021 2,612 2 View
I want to calculate terahertz spectra for my system but I am confuse about how to do it. The program I am using (crystal17) has two options, one is to perform frequency calculations at gamma point...
01 December 2020 907 2 View
I am a new user to crystal 17 (https://www.crystal.unito.it/index.php). I was trying to optimize a molecule using crystal17 but it is throwing following error: "ERROR **** INPUT3 **** n-D...
20 October 2020 5,549 2 View
I am new to material simulation and I am willing to learn the theoretical aspects like what is k point mesh, how to interpret band diagram, how born charge results in IR spectra etc. I have...
30 August 2020 1,418 8 View
I have one reaction as follows which I am studying using gaussian 16. reaction complex (RC)---> Intermediate (I1)--------> Transition state (TS1)-------> Product (P1). The relative...
22 May 2020 8,183 0 View
I am working at a reaction in which there is a following step H2C=O (triplet)---> CO + H2 (singlet) Whenever i tried to find transition state (TS) in this reaction, my run always results in...
29 April 2019 1,050 10 View
I am working on the reaction on the surface of water ice using ab initio and density functional methods. Suppose If a molecule A is adsorbed on the surface of water ice and B react with that...
16 October 2018 949 4 View
I have a cluster of water molecules. I want to model amorphous ice from that cluster. But for that I need to find out (best possible) minimum energy structure of that system. I tried Avogadro...
16 October 2018 7,556 7 View
I has a system in which I am optimizing a molecule with methanol and water molecules at B2PLYPD/6-311++(2p,d) level of theory with maxstep =10, tight convergence criteria and ultra-fine...
31 May 2018 1,473 2 View
in the several papers related with the observations of molecules in interstellar clouds i have read the notations like 303-212 and 404-313 transitions, b- type transitions, ΔKa = +1 transitions...
18 May 2017 5,544 2 View
I am a post graduate in Physics. Now I am working in the field of astrochemistry which deals with the formation of complex molecules in interstellar clouds which are detected via verity of...
05 May 2017 3,347 6 View
I have a reaction(bi-molecular) for which I have formed reaction complex, transition state and product. Now I want to calculate the rate constant for the reaction as well as the quantity of the...
08 April 2017 5,086 4 View
I am working of a reaction CH2 + CH2NH CH3CHNH. Before reacting those molecules I should form pre-reaction complex to have proper reference of energy to calculate barrier to the reaction (energy...
08 September 2016 2,602 3 View
I am working on the Ethanimine formation in the Interstellar medium by reaction CH2+CH2NH---->CH3CHNH. CH2 is taken in both singlet and triplet form. when I add water molecule in reaction...
06 August 2016 5,407 6 View
I am working on the reaction mechanism for pre-biotic molecules in amorphous interstellar ice. I have performed a reaction (ch2+ch2nh-->ch3chnh) both in gas phase and also with four water...
23 June 2016 841 9 View
I am trying to react CH2 (singlet) and CH2NH to form CH3CHNH. I form RC by placing the reactants at sum of the Vanderwall radius of the carbon atoms(1.7 angstrom for carbon) of CH2 and CH2NH as...
12 May 2016 4,492 1 View
I am working on a reaction in which there is a step involving the reaction between ch3 and ch2 . I have done this with wb97xd/6-311+g(d,p). now I want to repeat the same reaction which involves...
01 January 1970 5,302 3 View
