Potential Energy Surface Calculator

Map potentials from stretch, bend, and torsion coordinates. Inspect barriers and curvature through dynamic outputs. Model reaction behavior with clarity, speed, precision, and control.

Calculator Inputs

Use the fields below to model a simplified multidimensional molecular surface. The page remains single-column, while the inputs adapt to three, two, or one columns by screen size.

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Example Data Table

These sample coordinate sets use the current parameter values shown in the form. They help users compare wells, distortions, and higher-energy configurations.

Bond Length r (Å) Angle θ (°) Dihedral φ (°) Reaction Coordinate q Total Energy (kJ/mol)
1.02 106.0 180.0 -0.20 10.701923
1.10 109.5 180.0 0.00 0.000000
1.18 112.0 120.0 0.25 19.609036
1.24 114.0 60.0 0.35 21.603701

Formula Used

Total Surface Model

V(r, θ, φ, q) = E0 + De(1 - e-α(r-re))² + ½kθ(Δθrad)² + ½Vn[1 - cos(nΔφrad)] + λ(r-re)Δθrad + aqq⁴ - bq

This combines Morse stretching, harmonic angle bending, periodic torsion, stretch-angle coupling, and a quartic reaction coordinate term.

Bond Force and Curvature

∂V/∂r = 2Deαe-α(r-re)(1 - e-α(r-re)) + λΔθrad

Force along r = -∂V/∂r

∂²V/∂r² = 2Deα²[2e-2α(r-re) - e-α(r-re)]

Important: This calculator is a compact educational surface model. It is useful for screening trends, teaching concepts, and visualizing energy topology, but it does not replace full ab initio or density functional calculations.

How to Use This Calculator

  1. Use the CSV and PDF buttons to export the computed breakdown for reporting or study.

FAQs

1) What does a potential energy surface describe?

A potential energy surface shows how molecular energy changes when geometry changes. It helps identify stable structures, strained conformations, and likely transition regions during reactions.

2) Why is the Morse term used for bond stretching?

The Morse function models bond stretching more realistically than a simple harmonic curve. It captures asymmetry and better represents behavior as a bond moves toward dissociation.

3) Why are angles converted to radians internally?

Force constants for bending are commonly expressed against radian displacement. Converting degrees to radians keeps the energy terms mathematically consistent and easier to compare.

4) What does the reaction coordinate term do?

The quartic-minus-quadratic term can create wells or barrier-like behavior along an abstract reaction path. It is useful for exploring simplified isomerization or transition profiles.

5) How should I interpret positive and negative curvature?

Positive curvature suggests a locally stable direction, like a valley floor. Negative curvature suggests a barrier direction, where the geometry may resemble a transition or unstable region.

6) Are the results suitable for publication?

They are suitable for educational use, internal exploration, or quick comparison. Published mechanistic claims should rely on validated computational chemistry methods and calibrated parameters.

7) What units should I use?

Use bond lengths in angstroms, angles in degrees, and energy-related terms in kJ/mol. Keep parameter units consistent so each contribution remains physically interpretable.

8) Why might the total energy become negative?

Negative totals can occur when the offset and reaction-coordinate terms lower the reference level. The absolute value matters less than how energies compare across nearby geometries.

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Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.