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| '''Temperature jump''' is a technique used in the study of [[chemical kinetics]]. It usually involves the discharging of a capacitor (in the kV range) through a small volume (<mL) of a conducting solution containing the molecule/reaction to be studied. In some versions of the apparatus used, the solution is heated instead by the output of a pulsed laser which emits in the near infra-red. When laser heating is employed, the solution need not be conducting. In both cases, the temperature of the solution is caused to rise by a small amount in microseconds (or less in the case of laser heating). This allows the study of the shift in equilibrium of reactions that equilibrate in milliseconds (or microseconds with laser temperature jump), these changes most commonly being observed using [[absorption spectroscopy]] or [[fluorescence spectroscopy]]. Due to the small volumes involved the temperature of the solution returns to that of its surroundings in minutes.<ref>{{cite book|title=Handbook of biochemical kinetics|author=Daniel L. Purich, R. Donald Allison|year= 1999|publisher=Academic Press|isbn=0-12-568048-1}}</ref> | | Golda is what's created on my birth certification although it is not the name on clairvoyance [[http://www.aseandate.com/index.php?m=member_profile&p=profile&id=13352970 aseandate.com]] my [http://brazil.amor-amore.com/irboothe cheap psychic readings] birth certificate. My wife and I live in Mississippi but now I'm contemplating other choices. Invoicing is my profession. I am truly fond of handwriting but I can't make it my profession truly.<br><br>Also visit my web blog psychics online ([http://medialab.zendesk.com/entries/54181460-Will-You-Often-End-Up-Bored-Try-One-Of-These-Hobby-Ideas- visit the next web site]) |
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| The fractional extent of the reaction (''i.e.'' the percentage change in concentration of a measurable species) depends on the molar enthalpy change (Δ''H''°) between the reactants and products and the equilibrium position. If ''K'' is the equilibrium constant and ''dT'' is the change in temperature then the enthalpy change is given by the [[Van 't Hoff equation|Van't Hoff equation]]:
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| :<math> {\Delta H^o} = {RT^2}.\frac{d \ln K}{dT} </math>
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| where ''R'' is the [[Gas constant|universal gas constant]] and ''T'' is the [[Thermodynamic temperature|absolute temperature]]. When a single step in a reaction is perturbed in a temperature jump experiment, the reaction follows a single [[exponential decay]] function with the reciprocal [[time constant]] (1/τ) equal to the sum of the forward and reverse intrinsic rate constants. In more complex reaction networks, when multiple reaction steps are perturbed, then the reciprocal time constants are given by the [[eigenvalue]]s of the characteristic rate equations. The ability to observe intermediate steps in a reaction pathway is one of the attractive features of this technology.<ref>{{cite journal|last1=Urbanke|first1=C|last2=Wray|first2=J.|title=A fluorescence temperature-jump study of conformational transitions in myosin subfragment 1|journal=Biochemical Journal|year=2001|volume=358|pages=165–173|pmid=11485564|url=http://www.biochemj.org/bj/358/0165/3580165.pdf|issue=Pt 1|pmc=1222044}}</ref>
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| ==References==
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| {{reflist}}
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| [[Category:Chemical kinetics]]
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Latest revision as of 01:01, 24 August 2014
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