+ +
angle_style cosine/periodic command +
+Syntax: +
+angle_style cosine/periodic ++
Examples: +
+angle_style cosine/periodic +angle_coeff * 75.0 1 6 ++
Description: +
+The cosine/periodic angle style uses the following potential, which +is commonly used in the DREIDING force field, +particularly for organometallic systems where n = 4 might be used +for an octahedral complex and n = 3 might be used for a trigonal +center: +
+
+where C, B and n are coefficients defined for each angle type. +
+See (Mayo) for a description of the DREIDING force field +
+The following coefficients must be defined for each angle type via the +angle_coeff command as in the example above, or in +the data file or restart files read by the read_data +or read_restart commands: +
+- C (energy) +
- B = 1 or -1 +
- n = 1, 2, 3, 4, 5 or 6 for periodicity +
Note that the prefactor C is specified and not the overall force +constant K = C / n^2. When B = 1, it leads to a minimum for the +linear geometry. When B = -1, it leads to a maximum for the linear +geometry. +
+Restrictions: +
+This angle style can only be used if LAMMPS was built with the +"molecular" package (which it is by default). See the Making +LAMMPS section for more info on packages. +
+Related commands: +
+ +Default: none +
++ + + +
(Mayo) Mayo, Olfason, Goddard III, J Phys Chem, 94, 8897-8909 +(1990). +
+ diff --git a/doc/angle_cosine_periodic.txt b/doc/angle_cosine_periodic.txt new file mode 100644 index 0000000000..63a8fc52cd --- /dev/null +++ b/doc/angle_cosine_periodic.txt @@ -0,0 +1,64 @@ +"LAMMPS WWW Site"_lws - "LAMMPS Documentation"_ld - "LAMMPS Commands"_lc :c + +:link(lws,http://lammps.sandia.gov) +:link(ld,Manual.html) +:link(lc,Section_commands.html#comm) + +:line + +angle_style cosine/periodic command :h3 + +[Syntax:] + +angle_style cosine/periodic :pre + +[Examples:] + +angle_style cosine/periodic +angle_coeff * 75.0 1 6 :pre + +[Description:] + +The {cosine/periodic} angle style uses the following potential, which +is commonly used in the "DREIDING"_Section_howto.html#4_4 force field, +particularly for organometallic systems where {n} = 4 might be used +for an octahedral complex and {n} = 3 might be used for a trigonal +center: + +:c,image(Eqs/angle_cosine_periodic.jpg) + +where C, B and n are coefficients defined for each angle type. + +See "(Mayo)"_#Mayo for a description of the DREIDING force field + +The following coefficients must be defined for each angle type via the +"angle_coeff"_angle_coeff.html command as in the example above, or in +the data file or restart files read by the "read_data"_read_data.html +or "read_restart"_read_restart.html commands: + +C (energy) +B = 1 or -1 +n = 1, 2, 3, 4, 5 or 6 for periodicity :ul + +Note that the prefactor C is specified and not the overall force +constant K = C / n^2. When B = 1, it leads to a minimum for the +linear geometry. When B = -1, it leads to a maximum for the linear +geometry. + +[Restrictions:] + +This angle style can only be used if LAMMPS was built with the +"molecular" package (which it is by default). See the "Making +LAMMPS"_Section_start.html#2_3 section for more info on packages. + +[Related commands:] + +"angle_coeff"_angle_coeff.html + +[Default:] none + +:line + +:link(Mayo) +[(Mayo)] Mayo, Olfason, Goddard III, J Phys Chem, 94, 8897-8909 +(1990). diff --git a/doc/angle_style.html b/doc/angle_style.html index b1dce369e3..7ec349b11a 100644 --- a/doc/angle_style.html +++ b/doc/angle_style.html @@ -66,6 +66,7 @@ specified by the associated angle_coeff command