COMPASS force field - Revision history

Carl McBride: Converted references to Ref tag format

2013-04-10T10:40:18Z

Converted references to Ref tag format

← Older revision		Revision as of 12:40, 10 April 2013
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	'''COMPASS''' ('''C'''ondensed-phase '''O'''ptimized '''M'''olecular '''P'''otentials for '''A'''tomistic '''S'''imulation '''S'''tudies) is a member of the consistent family of [[force fields]] ([[CFF91]], [[PCFF]], [[CFF]] and COMPASS), which are closely related second-generation force fields. They were parameterized against a wide range of experimental observables for organic compounds containing [[hydrogen \|H]], [[carbon \|C]], [[nitrogen \|N]], [[oxygen \|O]], [[Sulfur \|S]], [[Phosphorus \|P]], halogen atoms and ions, alkali metal cations, and several biochemically important divalent metal cations. PCFF is based on CFF91, extended so as to have a broad coverage of organic polymers, (inorganic) metals, and [[zeolites]]. COMPASS is the first force field that has been parameterized and validated using condensed phase properties in addition to various and empirical data for molecules in isolation. Consequently, this forcefield enables accurate and simultaneous prediction of structural, conformational, vibrational, and thermo-physical properties for a broad range of molecules in isolation and in condensed phases.		'''COMPASS''' ('''C'''ondensed-phase '''O'''ptimized '''M'''olecular '''P'''otentials for '''A'''tomistic '''S'''imulation '''S'''tudies)
			<ref>[http://dx.doi.org/10.1021/jp980939v H. Sun "COMPASS: An ab Initio Force-Field Optimized for Condensed-Phase Applications - Overview with Details on Alkane and Benzene Compounds", Journal of Physical Chemistry B '''102''' pp. 7338–7364 (1998)]</ref>
			<ref>[http://dx.doi.org/10.1016/S1089-3156(98)00042-7 H. Sun, P. Ren and J. R. Fried "The COMPASS force field: parameterization and validation for phosphazenes", Computational and Theoretical Polymer Science '''8''' pp. 229-246 (1998)]</ref>
			<ref>[http://dx.doi.org/10.1021/jp991786u S. W. Bunte and H. Sun "Molecular Modeling of Energetic Materials: The Parameterization and Validation of Nitrate Esters in the COMPASS Force Field", Journal of Physical Chemistry B '''104''' pp. 2477-2489 (2000)]</ref>
			<ref>[http://dx.doi.org/10.1021/jp992913p Jie Yang, Yi Ren, An-min Tian and Huai Sun "COMPASS Force Field for 14 Inorganic Molecules, He, Ne, Ar, Kr, Xe, H2, O2, N2, NO, CO, CO2, NO2, CS2, and SO2, in Liquid Phases", Journal of Physical Chemistry B '''104''' pp. 4951-4957 (2000)]</ref>
			<ref>[http://dx.doi.org/10.1002/jcc.10316 Michael J. McQuaid, Huai Sun and David Rigby "Development and validation of COMPASS force field parameters for molecules with aliphatic azide chains", Journal of Computational Chemistry '''25''' pp. 61-71 (2004)]</ref>
			is a member of the consistent family of [[force fields]] ([[CFF91]], [[PCFF]], [[CFF]] and COMPASS), which are closely related second-generation force fields. They were parameterized against a wide range of experimental observables for organic compounds containing [[hydrogen \|H]], [[carbon \|C]], [[nitrogen \|N]], [[oxygen \|O]], [[Sulfur \|S]], [[Phosphorus \|P]], halogen atoms and ions, alkali metal cations, and several biochemically important divalent metal cations. PCFF is based on CFF91, extended so as to have a broad coverage of organic polymers, (inorganic) metals, and [[zeolites]]. COMPASS is the first force field that has been parameterized and validated using condensed phase properties in addition to various and empirical data for molecules in isolation. Consequently, this forcefield enables accurate and simultaneous prediction of structural, conformational, vibrational, and thermo-physical properties for a broad range of molecules in isolation and in condensed phases.
	==Functional form==		==Functional form==
	The COMPASS force field (~~Ref~~. 1 Eq. 1) consists of terms for bonds (<math>b</math>), angles (<math>\theta</math>), dihedrals (<math>\phi</math>), out-of-plane angles (<math>\chi</math>) as well as cross-terms, and two non-bonded functions, a [[Coulomb's law \|Coulombic function]] for electrostatic interactions and a [[9-6 Lennard-Jones potential]] for van der Waals interactions.		The COMPASS force field (Eq. 1 in Ref. 1) consists of terms for bonds (<math>b</math>), angles (<math>\theta</math>), dihedrals (<math>\phi</math>), out-of-plane angles (<math>\chi</math>) as well as cross-terms, and two non-bonded functions, a [[Coulomb's law \|Coulombic function]] for electrostatic interactions and a [[9-6 Lennard-Jones potential]] for van der Waals interactions.

	:<math>E_{\mathrm{total}} = E_b + E_{\theta} + E_{\phi} + E_{\chi} + E_{b,b'} + E_{b,\theta} + E_{b,\phi} + E_{\theta,\phi} +		:<math>E_{\mathrm{total}} = E_b + E_{\theta} + E_{\phi} + E_{\chi} + E_{b,b'} + E_{b,\theta} + E_{b,\phi} + E_{\theta,\phi} +
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	==Parameters==		==Parameters==
	==References==		==References==
	~~#[http:~~//dx.doi.org/10.1021/jp980939v H. Sun "COMPASS: An ab Initio Force-Field Optimized for Condensed-Phase Applications - Overview with Details on Alkane and Benzene Compounds", Journal of Physical Chemistry B '''102''' pp. 7338–7364 (1998)]		<references/>
	#[http://dx.doi.org/10.1016/S1089-3156(98)00042-7 H. Sun, P. Ren and J. R. Fried "The COMPASS force field: parameterization and validation for phosphazenes", Computational and Theoretical Polymer Science '''8''' pp. 229-246 (1998)]
	#[http://dx.doi.org/10.1021/jp991786u S. W. Bunte and H. Sun "Molecular Modeling of Energetic Materials: The Parameterization and Validation of Nitrate Esters in the COMPASS Force Field", Journal of Physical Chemistry B '''104''' pp. 2477-2489 (2000)]
	#[http://dx.doi.org/10.1021/jp992913p Jie Yang, Yi Ren, An-min Tian and Huai Sun "COMPASS Force Field for 14 Inorganic Molecules, He, Ne, Ar, Kr, Xe, H2, O2, N2, NO, CO, CO2, NO2, CS2, and SO2, in Liquid Phases", Journal of Physical Chemistry B '''104''' pp. 4951-4957 (2000)]
	#[http://dx.doi.org/10.1002/jcc.10316 Michael J. McQuaid, Huai Sun and David Rigby "Development and validation of COMPASS force field parameters for molecules with aliphatic azide chains", Journal of Computational Chemistry '''25''' pp. 61-71 (2004)]
	[[category: force fields]]		[[category: force fields]]

Carl McBride: /* Functional form */ Re-corrected the equation, is a + and not a cdot

2013-04-10T10:34:26Z

Functional form: Re-corrected the equation, is a + and not a cdot

← Older revision		Revision as of 12:34, 10 April 2013
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	:<math>E_{\mathrm{vdW}}= \sum_{ij} \epsilon_{ij} \left[ 2 \left(\frac{r_{ij}^0}{r_{ij}} \right)^9 -3 \left(\frac{r_{ij}^0}{r_{ij}} \right)^6\right]</math>		:<math>E_{\mathrm{vdW}}= \sum_{ij} \epsilon_{ij} \left[ 2 \left(\frac{r_{ij}^0}{r_{ij}} \right)^9 -3 \left(\frac{r_{ij}^0}{r_{ij}} \right)^6\right]</math>

	with the ~~following~~ [[combining rules]] (Ref. 1 ~~Eqs~~. ~~2 and~~ 3):		with the [[combining rules#Waldman-Hagler rules \|Waldman-Hagler combining rules ]] <ref>[http://dx.doi.org/10.1002/jcc.540140909 M. Waldman and A. T. Hagler "New combining rules for rare-gas Van der-Waals parameters", Journal of Computational Chemistry '''14''' pp. 1077-1084 (1993)]</ref> (Note, in Ref. 1 Eq. 3 seems to have a typographical error):

	:<math>r_{ij}^0 = \left( \frac{ (r_i^0)^6 + (r_j^0)^6 }{2} \right)^{1/6}</math>		:<math>r_{ij}^0 = \left( \frac{ (r_i^0)^6 + (r_j^0)^6 }{2} \right)^{1/6}</math>
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	and		and

	:<math>\epsilon_{ij} = 2 \sqrt{\epsilon_i \cdot \epsilon_j} \left( \frac{ (r_i^0)^3 \cdot (r_j^0)^3 }{ (r_i^0)^6 ~~\cdot~~ (r_j^0)^6 } \right)</math>		:<math>\epsilon_{ij} = 2 \sqrt{\epsilon_i \cdot \epsilon_j} \left( \frac{ (r_i^0)^3 \cdot (r_j^0)^3 }{ (r_i^0)^6 + (r_j^0)^6 } \right)</math>

	==Parameters==		==Parameters==

Carl McBride: /* Functional form */ Corrected equation

2013-04-10T10:23:02Z

Functional form: Corrected equation

← Older revision		Revision as of 12:23, 10 April 2013
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	and		and

	:<math>\epsilon_{ij} = 2 \sqrt{\epsilon_i \cdot \epsilon_j} \left( \frac{ (r_i^0)^3 \cdot (r_j^0)^3 }{ (r_i^0)^6 + (r_j^0)^6 } \right)</math>		:<math>\epsilon_{ij} = 2 \sqrt{\epsilon_i \cdot \epsilon_j} \left( \frac{ (r_i^0)^3 \cdot (r_j^0)^3 }{ (r_i^0)^6 \cdot (r_j^0)^6 } \right)</math>

	==Parameters==		==Parameters==

67.242.95.31 at 03:30, 28 March 2013

2013-03-28T03:30:51Z

← Older revision		Revision as of 05:30, 28 March 2013
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	and		and

	:<math>\epsilon_{ij} = 2 \sqrt{\epsilon_i \cdot \epsilon_j} \left( \frac{ (r_i^0)^3 \cdot (r_j^0)^3 }{ (r_i^0)^6 ~~\cdot~~ (r_j^0)^6 } \right)</math>		:<math>\epsilon_{ij} = 2 \sqrt{\epsilon_i \cdot \epsilon_j} \left( \frac{ (r_i^0)^3 \cdot (r_j^0)^3 }{ (r_i^0)^6 + (r_j^0)^6 } \right)</math>

	==Parameters==		==Parameters==

Carl McBride: Reverted edits by 70.135.118.126 (talk) to last revision by Nice and Tidy

2012-01-04T14:32:32Z

Reverted edits by 70.135.118.126 (talk) to last revision by Nice and Tidy

← Older revision		Revision as of 16:32, 4 January 2012
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	#[http://dx.doi.org/10.1002/jcc.10316 Michael J. McQuaid, Huai Sun and David Rigby "Development and validation of COMPASS force field parameters for molecules with aliphatic azide chains", Journal of Computational Chemistry '''25''' pp. 61-71 (2004)]		#[http://dx.doi.org/10.1002/jcc.10316 Michael J. McQuaid, Huai Sun and David Rigby "Development and validation of COMPASS force field parameters for molecules with aliphatic azide chains", Journal of Computational Chemistry '''25''' pp. 61-71 (2004)]
	[[category: force fields]]		[[category: force fields]]
	~~[http://www.prlog.org/11289974-phone-number-lookup-verizon-phone-number-reverse-lookup-to-get-information-you-need-quickly.html phone address lookup]~~

	~~[http://thetvtopc.com/Reverse_Cell_Phone_Lookup_Number reverse phone number lookup]~~

70.135.118.126 at 05:59, 4 January 2012

2012-01-04T05:59:08Z

← Older revision		Revision as of 07:59, 4 January 2012
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	#[http://dx.doi.org/10.1002/jcc.10316 Michael J. McQuaid, Huai Sun and David Rigby "Development and validation of COMPASS force field parameters for molecules with aliphatic azide chains", Journal of Computational Chemistry '''25''' pp. 61-71 (2004)]		#[http://dx.doi.org/10.1002/jcc.10316 Michael J. McQuaid, Huai Sun and David Rigby "Development and validation of COMPASS force field parameters for molecules with aliphatic azide chains", Journal of Computational Chemistry '''25''' pp. 61-71 (2004)]
	[[category: force fields]]		[[category: force fields]]
			[http://www.prlog.org/11289974-phone-number-lookup-verizon-phone-number-reverse-lookup-to-get-information-you-need-quickly.html phone address lookup]

			[http://thetvtopc.com/Reverse_Cell_Phone_Lookup_Number reverse phone number lookup]

Nice and Tidy: COMPASS moved to COMPASS force field

2010-03-05T11:47:40Z

COMPASS moved to COMPASS force field

← Older revision	Revision as of 13:47, 5 March 2010
(No difference)

Carl McBride: /* Functional form */ slight tidy.

2010-03-05T11:00:41Z

Functional form: slight tidy.

← Older revision		Revision as of 13:00, 5 March 2010
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	'''COMPASS''' ('''C'''ondensed-phase '''O'''ptimized '''M'''olecular '''P'''otentials for '''A'''tomistic '''S'''imulation '''S'''tudies) is a member of the consistent family of [[force fields]] ([[CFF91]], [[PCFF]], [[CFF]] and COMPASS), which are closely related second-generation force fields. They were parameterized against a wide range of experimental observables for organic compounds containing [[hydrogen \|H]], [[carbon \|C]], [[nitrogen \|N]], [[oxygen \|O]], [[Sulfur \|S]], [[Phosphorus \|P]], halogen atoms and ions, alkali metal cations, and several biochemically important divalent metal cations. PCFF is based on CFF91, extended so as to have a broad coverage of organic polymers, (inorganic) metals, and [[zeolites]]. COMPASS is the first force field that has been parameterized and validated using condensed phase properties in addition to various and empirical data for molecules in isolation. Consequently, this forcefield enables accurate and simultaneous prediction of structural, conformational, vibrational, and thermo-physical properties for a broad range of molecules in isolation and in condensed phases.		'''COMPASS''' ('''C'''ondensed-phase '''O'''ptimized '''M'''olecular '''P'''otentials for '''A'''tomistic '''S'''imulation '''S'''tudies) is a member of the consistent family of [[force fields]] ([[CFF91]], [[PCFF]], [[CFF]] and COMPASS), which are closely related second-generation force fields. They were parameterized against a wide range of experimental observables for organic compounds containing [[hydrogen \|H]], [[carbon \|C]], [[nitrogen \|N]], [[oxygen \|O]], [[Sulfur \|S]], [[Phosphorus \|P]], halogen atoms and ions, alkali metal cations, and several biochemically important divalent metal cations. PCFF is based on CFF91, extended so as to have a broad coverage of organic polymers, (inorganic) metals, and [[zeolites]]. COMPASS is the first force field that has been parameterized and validated using condensed phase properties in addition to various and empirical data for molecules in isolation. Consequently, this forcefield enables accurate and simultaneous prediction of structural, conformational, vibrational, and thermo-physical properties for a broad range of molecules in isolation and in condensed phases.
	==Functional form==		==Functional form==
	The COMPASS force field (Ref. 1 Eq. 1) consists of terms for bonds (<math>b</math>), angles (<math>\theta</math>), dihedrals (<math>\phi</math>), out-of-plane angles (<math>\chi</math>) as well as cross-terms, [[Coulomb's law \|Coulombic ~~charges~~]] and a [[9-6 Lennard-Jones potential ~~\| 9-6 non-bonded term~~]]		The COMPASS force field (Ref. 1 Eq. 1) consists of terms for bonds (<math>b</math>), angles (<math>\theta</math>), dihedrals (<math>\phi</math>), out-of-plane angles (<math>\chi</math>) as well as cross-terms, and two non-bonded functions, a [[Coulomb's law \|Coulombic function]] for electrostatic interactions and a [[9-6 Lennard-Jones potential]] for van der Waals interactions.


	:<math>E_{\mathrm{total}} = E_b + E_{\theta} + E_{\phi} + E_{\chi} + E_{b,b'} + E_{b,\theta} + E_{b,\phi} + E_{\theta,\phi} +		:<math>E_{\mathrm{total}} = E_b + E_{\theta} + E_{\phi} + E_{\chi} + E_{b,b'} + E_{b,\theta} + E_{b,\phi} + E_{\theta,\phi} +
	E_{\theta,\theta'} + E_{\theta,\theta',\phi} + E_{q} + E_{\mathrm{~~non-bonded~~}}</math>		E_{\theta,\theta'} + E_{\theta,\theta',\phi} + E_{q} + E_{\mathrm{vdW}}</math>

	where		where
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	and		and

	:<math>E_{\mathrm{~~non-bonded~~}}= \sum_{ij} \epsilon_{ij} \left[ 2 \left(\frac{r_{ij}^0}{r_{ij}} \right)^9 -3 \left(\frac{r_{ij}^0}{r_{ij}} \right)^6\right]</math>		:<math>E_{\mathrm{vdW}}= \sum_{ij} \epsilon_{ij} \left[ 2 \left(\frac{r_{ij}^0}{r_{ij}} \right)^9 -3 \left(\frac{r_{ij}^0}{r_{ij}} \right)^6\right]</math>

	with the following [[combining rules]] (Ref. 1 Eqs. 2 and 3):		with the following [[combining rules]] (Ref. 1 Eqs. 2 and 3):

Carl McBride: /* Functional form */ Added combining rules

2010-03-05T10:49:13Z

Functional form: Added combining rules

← Older revision		Revision as of 12:49, 5 March 2010
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	:<math>E_{\mathrm{non-bonded}}= \sum_{ij} \epsilon_{ij} \left[ 2 \left(\frac{r_{ij}^0}{r_{ij}} \right)^9 -3 \left(\frac{r_{ij}^0}{r_{ij}} \right)^6\right]</math>		:<math>E_{\mathrm{non-bonded}}= \sum_{ij} \epsilon_{ij} \left[ 2 \left(\frac{r_{ij}^0}{r_{ij}} \right)^9 -3 \left(\frac{r_{ij}^0}{r_{ij}} \right)^6\right]</math>

			with the following [[combining rules]] (Ref. 1 Eqs. 2 and 3):

			:<math>r_{ij}^0 = \left( \frac{ (r_i^0)^6 + (r_j^0)^6 }{2} \right)^{1/6}</math>

			and

			:<math>\epsilon_{ij} = 2 \sqrt{\epsilon_i \cdot \epsilon_j} \left( \frac{ (r_i^0)^3 \cdot (r_j^0)^3 }{ (r_i^0)^6 \cdot (r_j^0)^6 } \right)</math>

	==Parameters==		==Parameters==
	==References==		==References==

Carl McBride: Finished functional form

2010-03-05T10:36:01Z

Finished functional form

← Older revision		Revision as of 12:36, 5 March 2010
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	'''COMPASS''' ('''C'''ondensed-phase '''O'''ptimized '''M'''olecular '''P'''otentials for '''A'''tomistic '''S'''imulation '''S'''tudies) is a member of the consistent family of [[force fields]] ([[CFF91]], [[PCFF]], [[CFF]] and COMPASS), which are closely related second-generation force fields. They were parameterized against a wide range of experimental observables for organic compounds containing [[hydrogen \|H]], [[carbon \|C]], [[nitrogen \|N]], [[oxygen \|O]], [[Sulfur \|S]], [[Phosphorus \|P]], halogen atoms and ions, alkali metal cations, and several biochemically important divalent metal cations. PCFF is based on CFF91, extended so as to have a broad coverage of organic polymers, (inorganic) metals, and [[zeolites]]. COMPASS is the first force field that has been parameterized and validated using condensed phase properties in addition to various and empirical data for molecules in isolation. Consequently, this forcefield enables accurate and simultaneous prediction of structural, conformational, vibrational, and thermo-physical properties for a broad range of molecules in isolation and in condensed phases.		'''COMPASS''' ('''C'''ondensed-phase '''O'''ptimized '''M'''olecular '''P'''otentials for '''A'''tomistic '''S'''imulation '''S'''tudies) is a member of the consistent family of [[force fields]] ([[CFF91]], [[PCFF]], [[CFF]] and COMPASS), which are closely related second-generation force fields. They were parameterized against a wide range of experimental observables for organic compounds containing [[hydrogen \|H]], [[carbon \|C]], [[nitrogen \|N]], [[oxygen \|O]], [[Sulfur \|S]], [[Phosphorus \|P]], halogen atoms and ions, alkali metal cations, and several biochemically important divalent metal cations. PCFF is based on CFF91, extended so as to have a broad coverage of organic polymers, (inorganic) metals, and [[zeolites]]. COMPASS is the first force field that has been parameterized and validated using condensed phase properties in addition to various and empirical data for molecules in isolation. Consequently, this forcefield enables accurate and simultaneous prediction of structural, conformational, vibrational, and thermo-physical properties for a broad range of molecules in isolation and in condensed phases.
	==Functional form==		==Functional form==
	(Ref. 1 Eq. 1)		The COMPASS force field (Ref. 1 Eq. 1) consists of terms for bonds (<math>b</math>), angles (<math>\theta</math>), dihedrals (<math>\phi</math>), out-of-plane angles (<math>\chi</math>) as well as cross-terms, [[Coulomb's law \|Coulombic charges]] and a [[9-6 Lennard-Jones potential \| 9-6 non-bonded term]]

	:<math>E_{\mathrm{total}} = E_b + E_{\theta} + E_{\phi} + E_{\chi} + E_{b,b'} + E_{b,\theta} </math>
			:<math>E_{\mathrm{total}} = E_b + E_{\theta} + E_{\phi} + E_{\chi} + E_{b,b'} + E_{b,\theta} + E_{b,\phi} + E_{\theta,\phi} +
			E_{\theta,\theta'} + E_{\theta,\theta',\phi} + E_{q} + E_{\mathrm{non-bonded}}</math>

	where		where

	:<math>E_b = \sum_b \left[ k_2 (b-b_0)^2 + k_3 (b-b_0)^3 + k_4 (b-b_0)^4 \right]</math>		:<math>E_b = \sum_b \left[ k_2 (b-b_0)^2 + k_3 (b-b_0)^3 + k_4 (b-b_0)^4 \right]</math>
	:<math>E_{\theta} = \~~sum_b~~ \left[ k_2 (\theta-\theta_0)^2 + k_3 (\theta-\theta_0)^3 + k_4 (\theta-\theta_0)^4 \right]</math>
			:<math>E_{\theta} = \sum_{\theta} \left[ k_2 (\theta-\theta_0)^2 + k_3 (\theta-\theta_0)^3 + k_4 (\theta-\theta_0)^4 \right]</math>

	:<math>E_{\phi} = \sum_{\phi} \left[ k_1(1-\cos \phi) + k_2(1-\cos 2\phi) + k_3(1-\cos 3\phi) \right]</math>		:<math>E_{\phi} = \sum_{\phi} \left[ k_1(1-\cos \phi) + k_2(1-\cos 2\phi) + k_3(1-\cos 3\phi) \right]</math>

	:<math>E_{\chi} = \sum_{\chi} k_2 \chi^2</math>		:<math>E_{\chi} = \sum_{\chi} k_2 \chi^2</math>

	:<math>E_{b,b'} = \sum_{b,b'} k(b-b_0)(b'-b_0')</math>		:<math>E_{b,b'} = \sum_{b,b'} k(b-b_0)(b'-b_0')</math>

	:<math>E_{b,\theta} = \sum_{b,\theta} k(b-b_0)(\theta-\theta_0)</math>		:<math>E_{b,\theta} = \sum_{b,\theta} k(b-b_0)(\theta-\theta_0)</math>

	:<math>E_{b,\phi} = \sum_{b,\phi} (b-b_0) \left[k_1 cos \phi + k_2 cos 2\phi + k_3 cos 3\phi\right]</math>		:<math>E_{b,\phi} = \sum_{b,\phi} (b-b_0) \left[k_1 cos \phi + k_2 cos 2\phi + k_3 cos 3\phi\right]</math>

	:<math>E_{\theta,\phi} = \sum_{\theta,\phi} (\theta-\theta_0) \left[k_1 cos \phi + k_2 cos 2\phi + k_3 cos 3\phi\right]</math>		:<math>E_{\theta,\phi} = \sum_{\theta,\phi} (\theta-\theta_0) \left[k_1 cos \phi + k_2 cos 2\phi + k_3 cos 3\phi\right]</math>

	:<math>E_{\theta,\theta'} = \sum_{\theta,\theta'} k(\theta-\theta_0)(\theta'-\theta_0')</math>		:<math>E_{\theta,\theta'} = \sum_{\theta,\theta'} k(\theta-\theta_0)(\theta'-\theta_0')</math>
	:<math>E_{\theta,\theta',\phi} = \sum_{\theta,\theta'} k(\theta-\theta_0)(\theta'-\theta_0')\cos \phi</math>
			:<math>E_{\theta,\theta',\phi} = \sum_{\theta,\theta',\phi} k(\theta-\theta_0)(\theta'-\theta_0')\cos \phi</math>

			:<math>E_{q}=\sum_{ij} \frac{q_i q_j}{r_{ij}}</math>

			and

			:<math>E_{\mathrm{non-bonded}}= \sum_{ij} \epsilon_{ij} \left[ 2 \left(\frac{r_{ij}^0}{r_{ij}} \right)^9 -3 \left(\frac{r_{ij}^0}{r_{ij}} \right)^6\right]</math>
			==Parameters==
	==References==		==References==
	#[http://dx.doi.org/10.1021/jp980939v H. Sun "COMPASS: An ab Initio Force-Field Optimized for Condensed-Phase Applications - Overview with Details on Alkane and Benzene Compounds", Journal of Physical Chemistry B '''102''' pp. 7338–7364 (1998)]		#[http://dx.doi.org/10.1021/jp980939v H. Sun "COMPASS: An ab Initio Force-Field Optimized for Condensed-Phase Applications - Overview with Details on Alkane and Benzene Compounds", Journal of Physical Chemistry B '''102''' pp. 7338–7364 (1998)]