what is the criterion for oscillator strength of dark state vs. bright states obtained from LR-TDDFT (Casida approach)?

03 April 2017 2,853 2 View

Which one is more pi-deficient: bipyridine or benzimidazole?

I need comparative data about pi-electron distribution over benzimidazole and bipyridine groups. Is there any simple way to calculate it? Furthermore, if the above character will change when we...

05 June 2014 8,593 3 View

Is there any direct way to extract the "electronic density of excited state" from GAMESS (US) output?

I did a excited state calculation with GAMESS by adding tdprt=.true. which writes some properties of the excited state in output (for example, the dipole moment.) Now, I'd like to know about...

03 April 2014 1,232 1 View

How to predict the deprotonation of a molecule in a solvent?

I want to do ab-initio calculation for an organic D-pai-A dye in presence of a solvent, and this molecule has a cyanoacetic group as an anchoring group, I am not sure about its neutral or anion...

09 October 2013 5,774 15 View

Where can I find the parameters needed to define acetonitrile as a solvent in gamess input?

Acetonitrile in GAMESS. I want to do DFT calculation including PCM model in Gamess, but I have problem to define that as a solvent. As my best knowledge, there is many solvents in DMS table but I...

09 October 2013 9,325 1 View

How to set nstate for TDDFT calculations?

I want to calculate UV/Vis for an organic dye, and I found that increasing the "nstates" in tddft calculations, changes the value of first excitation energy, for example when I change nstate from...

09 October 2013 547 5 View

What is the "Analytical form of Hessian matrix for freq calculation"?

I am looking for the analytical derivative algorithms which are accessible in quantum chemistry, If in g09 or Gamess the harmonic approximation used to make analytical terms for energy derivatives?

07 August 2013 2,199 1 View

Dipole-Dipole interaction and covarage of surface?

Please consider the adsorption of some organic molecules at the surface of semiconductor. Can the dipole dipole interaction between the adsorbent molecules affect the surface coverage or...

06 July 2013 8,279 2 View

What is the physical origin of the numerical value of fwhm (~0.4 eV, or 3000cm-1 in gausssum) in uv/vis spectrum ?

Usually, fwhm considered about 3000 cm-1 in many papers, but this is a very big number in comparison with the corresponding value for Gaussian broadening, in text books--it is about 0.05 cm-1 for...

05 June 2013 10,000 4 View

error in running a model in Abaqus

Excessive rotation of nodes in node set ErrNodeExcessRotation-Step1

17 August 2021 0 0 View

error in modelling model in Abaqus

Excessive rotation of nodes in node set ErrNodeExcessRotation-Step1

17 August 2021 0 0 View

MD MOE RMSD

How to calculate the RMSD values for a MD simulation using MOE?

07 August 2021 0 0 View

MD MOE RMSD

How to calculate the RMSD values for a MD simulation using MOE?

07 August 2021 0 0 View

MGL tools

20 June 2021 0 0 View

fatal error

When I tried to energy minimization my system, I got fatal error as below. Fatal error: Atomtype opls_116 not found Although I've already added this line: ; include water #include "oplsaa.ff/spc.itp" to [molecultype] directive in my topology.

16 June 2021 0 0 View

fatal error

When I tried to energy minimization my system, I got fatal error as below. Fatal error: Atomtype opls_116 not found Although I've already added this line: ; include water #include "oplsaa.ff/spc.itp" to [molecultype] directive in my topology.

16 June 2021 0 0 View

fatal error

When I tried to energy minimization my system, I got fatal error as below. Fatal error: Atomtype opls_116 not found Although I've already added this line: ; include water #include "oplsaa.ff/spc.itp" to [molecultype] directive in my topology.

16 June 2021 0 0 View

fatal error

When I tried to energy minimization my system, I got fatal error as below. Fatal error: Atomtype opls_116 not found Although I've already added this line: ; include water #include "oplsaa.ff/spc.itp" to [molecultype] directive in my topology.

16 June 2021 0 0 View

what is the simplest definition of ion exchange capacity

What this unit identifies for the ion exchange capacity ca. 0.92 meq. g-1. I am a newcomer in the membrane area. I just started. I highly appreciate your help

08 May 2021 0 0 View