From 312bdcbddd0c25297598c679cb427277aa991679 Mon Sep 17 00:00:00 2001 From: Axel Kohlmeyer Date: Mon, 10 Mar 2025 06:26:37 -0400 Subject: [PATCH] correct and clarify statements about the potentials and their relations to each other --- doc/src/bond_harmonic.rst | 2 ++ doc/src/bond_harmonic_shift.rst | 17 +++++++++++------ doc/src/bond_harmonic_shift_cut.rst | 11 ++++++++--- 3 files changed, 21 insertions(+), 9 deletions(-) diff --git a/doc/src/bond_harmonic.rst b/doc/src/bond_harmonic.rst index a76cc54746..70e652bb4a 100644 --- a/doc/src/bond_harmonic.rst +++ b/doc/src/bond_harmonic.rst @@ -60,6 +60,8 @@ Related commands """""""""""""""" :doc:`bond_coeff `, :doc:`delete_bonds ` +:doc:`bond style harmonic/shift `, +:doc:`bond style harmonic/shift/cut ` Default """"""" diff --git a/doc/src/bond_harmonic_shift.rst b/doc/src/bond_harmonic_shift.rst index 43e10bde00..e57d464af8 100644 --- a/doc/src/bond_harmonic_shift.rst +++ b/doc/src/bond_harmonic_shift.rst @@ -31,9 +31,15 @@ the potential E = \frac{U_{\text{min}}}{(r_0-r_c)^2} \left[ (r-r_0)^2-(r_c-r_0)^2 \right] -where :math:`r_0` is the equilibrium bond distance, and :math:`r_c` the critical distance. -The potential is :math:`-U_{\text{min}}` at :math:`r0` and zero at :math:`r_c`. The spring constant is -:math:`k = U_{\text{min}} / [ 2 (r_0-r_c)^2]`. +where :math:`r_0` is the equilibrium bond distance, and :math:`r_c` the +critical distance. The potential energy has the value +:math:`-U_{\text{min}}` at :math:`r_0` and zero at :math:`r_c`. This +bond style differs from :doc:`bond_style harmonic ` +by the value of the potential energy. + +The equivalent spring constant value *K* for use with :doc:`bond_style +harmonic ` can be computed using :math:`K = +U_{\text{min}} / [(r_0-r_c)^2]`. The following coefficients must be defined for each bond type via the :doc:`bond_coeff ` command as in the example above, or in @@ -41,9 +47,7 @@ the data file or restart files read by the :doc:`read_data ` or :doc:`read_restart ` commands: * :math:`U_{\text{min}}` (energy) - * :math:`r_0` (distance) - * :math:`r_c` (distance) ---------- @@ -63,7 +67,8 @@ Related commands """""""""""""""" :doc:`bond_coeff `, :doc:`delete_bonds `, -:doc:`bond_harmonic ` +:doc:`bond style harmonic `, +:doc:`bond style harmonic/shift/cut ` Default """"""" diff --git a/doc/src/bond_harmonic_shift_cut.rst b/doc/src/bond_harmonic_shift_cut.rst index d8d4a792b7..964ae4b9ba 100644 --- a/doc/src/bond_harmonic_shift_cut.rst +++ b/doc/src/bond_harmonic_shift_cut.rst @@ -31,9 +31,14 @@ uses the potential E = \frac{U_{\text{min}}}{(r_0-r_c)^2} \left[ (r-r_0)^2-(r_c-r_0)^2 \right] -where :math:`r_0` is the equilibrium bond distance, and rc the critical distance. -The bond potential is zero for distances :math:`r > r_c`. The potential is :math:`-U_{\text{min}}` -at :math:`r_0` and zero at :math:`r_c`. The spring constant is :math:`k = U_{\text{min}} / [ 2 (r_0-r_c)^2]`. +where :math:`r_0` is the equilibrium bond distance, and :math:`r_c` the +critical distance. The bond potential is zero and thus its force also +zero for distances :math:`r > r_c`. The potential energy has the value +:math:`-U_{\text{min}}` at :math:`r_0` and zero at :math:`r_c`. + +The equivalent spring constant value *K* for use with :doc:`bond_style +harmonic ` for :math:`r <= r_c`, can be computed using +:math:`K = U_{\text{min}} / [(r_0-r_c)^2]` The following coefficients must be defined for each bond type via the :doc:`bond_coeff ` command as in the example above, or in