Q value - Revision history

KevinYager at 16:26, 30 September 2014

2014-09-30T16:26:49Z

2014-09-30T14:01:32Z

2014-06-14T16:03:39Z

2014-06-13T17:36:00Z

2014-06-10T12:55:08Z

2014-06-09T18:54:43Z

‎Lookup table

2014-06-09T18:49:34Z

‎Lookup table

2014-06-09T18:25:55Z

‎Lookup table

2014-06-09T17:26:39Z

‎Lookup table

2014-06-09T17:25:56Z

‎Lookup table

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-A given '''q value'''  ([[momentum transfer]] in [[reciprocal-space]]) corresponds to a real-space distance (''d'') of:
+A given '''q value'''  ([[momentum transfer]] in [[reciprocal-space]]) corresponds to a [[real-space]] distance (''d'') of:
 :<math>
 q = \frac{2\pi}{d}

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 * Large angle (0.2-2 Å<sup>−1</sup>): Molecular packing distances (0.3-3 nm). For instance, aromatic rings tend to pi-pi stack with a 0.3-0.4 nm repeat distance.
 * Medium angle (0.03-0.3 Å<sup>−1</sup>): Macromolecular distances (2-20 nm). For instance, polymers often crystallize into chain-folded lamellae with a period of 2-10 nm.
-* Small angle (0.0002-0.04 Å<sup>−1</sup>): Nanoscale distances (15-300 nm). For instance, block-copolymers and nanoparticle [[superlattice]]s tend to organize in this size regime.
+* Small angle (0.0002-0.04 Å<sup>−1</sup>): Nanoscale distances (15-300 nm). For instance, [[block-copolymers]] and nanoparticle [[superlattice]]s tend to organize in this size regime.
 * Ultra-small angle (<0.0006 Å<sup>−1</sup>): Micron sizes (>1 µm).

← Older revision		Revision as of 16:03, 14 June 2014
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	[[Image:D vs q.png\|400px\|center]]		[[Image:D vs q.png\|400px\|center]]
		+
		+	==Peak position==
		+	The ''q''-value for a peak gives a hint about what kinds of structure is producing the scattering:
		+	* Very large angle (0.5-4 Å<sup>−1</sup>): Atomic packing distances (1-10 Å).
		+	* Large angle (0.2-2 Å<sup>−1</sup>): Molecular packing distances (0.3-3 nm). For instance, aromatic rings tend to pi-pi stack with a 0.3-0.4 nm repeat distance.
		+	* Medium angle (0.03-0.3 Å<sup>−1</sup>): Macromolecular distances (2-20 nm). For instance, polymers often crystallize into chain-folded lamellae with a period of 2-10 nm.
		+	* Small angle (0.0002-0.04 Å<sup>−1</sup>): Nanoscale distances (15-300 nm). For instance, block-copolymers and nanoparticle [[superlattice]]s tend to organize in this size regime.
		+	* Ultra-small angle (<0.0006 Å<sup>−1</sup>): Micron sizes (>1 µm).
		+

	==Lookup table==		==Lookup table==

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 A given '''q value'''  ([[momentum transfer]] in [[reciprocal-space]]) corresponds to a real-space distance (''d'') of:
 :<math>
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 </math>
 One must be careful, however. A peak in reciprocal-space corresponds to a repeating ''structure'' in the realspace [[lattice]]; i.e. this may or may not correspond directly to particle-particle spacings.
 ==Lookup table==

← Older revision		Revision as of 12:55, 10 June 2014
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		+	[[Image:D vs q.png\|400px\|right]]
		+
	A given '''q value''' ([[momentum transfer]] in [[reciprocal-space]]) corresponds to a real-space distance (''d'') of:		A given '''q value''' ([[momentum transfer]] in [[reciprocal-space]]) corresponds to a real-space distance (''d'') of:
	:<math>		:<math>