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Questions related to Computational Chemistry
I am doing DFT calculation on sugar lipid system. The command I used is "#n opt freq=noraman b3lyp/6-311++g(d,p) geom=connectivity scf=qc". I get error message as below: LinEq1: Iter=992 NonCon= 1...
01 January 2015 8,734 7 View
In Gaussian-based quantum chemistry codes, the total spin in the z-direction must be specified at the start of the calculation. By contrast, in plane-wave codes the magnetization of each atom is...
12 December 2014 4,876 12 View
Hi, i have a problem relating with the aspen plus . i want simulate the fertilizer plant using aspen plus .is it possible to use two or more then two thermodynamic property method in single aspen...
12 December 2014 657 3 View
I am trying to compute the potential energy curves of different symmetry for NO diatomic molecule using MOLPRO.
12 December 2014 6,648 1 View
Now, I just declare the number of states by using NSTATE flag. I supposse this flag concerns electronic states. What about vibrational?? The issue is about absorption, I try to determine...
12 December 2014 1,907 11 View
I have two zinc coordinations in my globular protein, using Amberssff in Gromacs. Partial charges have been calculated for both using PyRED. One zinc remains in place using a non-bonded model,...
12 December 2014 8,229 2 View
I am going to developing models for prediction of melting point of some hydrocarbons component with QSPR method. i have one sdf file which contain those hydrocarbons structure so before...
12 December 2014 6,495 9 View
Hi, I'm doing some calculations on Hyperchem for my research and most sources that I read say the orbital criterion should be set at 3 for both the occupied and unoccupied when calculating the...
12 December 2014 5,718 0 View
I want to do a simulation with restraints using Extrabonds. Does anybody know how to do it?
12 December 2014 10,083 1 View
The ground state of NO splits into two spin orbit states (2pi1/2 and 2pi3/2). Does anybody know how to compute the energies of these states using either Gaussian or Molpro?
12 December 2014 3,507 2 View
I am performing a calculation in ORCA 2.7.0. Geometry optimization successfully converged, but OUT file generation shows lambda error. I have the txt file with me, if anyone is interested then I...
12 December 2014 1,701 5 View
Calculating vertical detachment energy or electron affinities for a "Dipole Bound Anion" is not as straightforward as the "Valance Bound Anion". I was wondering if anyone had experience with ...
12 December 2014 4,844 3 View
I wanted to calculate excited state propeties of molecule considering double excitation. From literature I know how to determine the character of excited state of pentacene,tetracene etc. ,MRMP...
12 December 2014 877 0 View
I want to calculate the energy of Fe atom. In G09, orbitals occupancies are integer and accordingly one electron occupies one of the down spin d states. This makes the d state non degenerate. So,...
12 December 2014 5,309 4 View
Couldn't figure out the use of the Hessian matrix in computational chemistry.
12 December 2014 2,981 5 View
I tried simulation of liquid oxygen at 70 K but after NVE simulation temperature is rising to 80-90 K. which is the boiling point of oxygen. I wanted to simulate liquid oxygen. Is it possible to...
12 December 2014 2,954 3 View
As both the layers have different cell dimensions.
12 December 2014 7,657 3 View
I am looking for a freeware program for Windows which can take simple input file formats like SMILES, PDB, MOL etc. to give a 2D chemical structure, instead of manually drawing the whole structure.
11 November 2014 7,241 3 View
I used Attension Theta to measure the water contact angle of my sample. Due to some problems with curve fitting, the contact angle value could not be given by the software. Now I have the image of...
11 November 2014 3,048 14 View
Finding the transition state of the hydrolysis of HCOCl with OH-.
11 November 2014 9,223 1 View
My recent research interests have moved me into quantum chem calculations and I have some questions regarding GAMESS that I hope you may be able to address. I have been investigating the effect of...
11 November 2014 1,277 4 View
I'm trying to run some simple QM calculations using GAMESS, but it seems to give a wrong result. The expected value of total energy is -24.258337146 a.u. while GAMESS returns 490.9315519299. I'm...
11 November 2014 7,122 5 View
I need to run opt and freq with dioxane solvent but I did not do. because dioxane isn't in solvent list in G09W. However I try CPCM-other button and write 2.2099. but I did't work it. Can anyone...
11 November 2014 5,948 2 View
I am looking for a free software providing ELF basin analysis. While "TopMod" and "MULTIWFN" can perform such analysis, former must be executed on LINUX operating system and, the later, is very...
11 November 2014 7,585 2 View