EÐL620M / Life in the Universe Life in the Universe Astrophysics – chemistry – Biology – earth-/planetary sciences Atoms - chemical bond Carbon chemical bond Atoms and molecules in space ; Informations derived from spectroscopy Molecules in the universe ; Existance and formation Interactions between light and matter ; photochemistry, photoionization, photofragmentation Thermochemistry in the Universe Biochemistry

Entropy (S total ) of the Universe increases i.e.  S total >0 for an isolated system path S total S total (1) S total (2)  S total S total (max) dS total >0 dS total = 0 Changes / evolutions DO occur equilibrium: Changes / evolutions Do not occur ?

i.e.  S total >0 for an isolated system  S galaxies 0  S total =  S galaxies +  S other >0 Entropy (S total ) of the Universe increases

i.e.  S total >0 for an isolated system Entropy (S total ) increases i.e. Changes / evolutions occur  s solar systems 0  S total =  s solar systems +  S other >0

i.e.  S total >0 for an isolated system Entropy (S total ) increases i.e. Changes / evolutions occur  S reaction 0  S total =  S reaction +  S other >0 A(l)B(l) A(l) + B(l) C(s)

i.e.  S total >0 for an isolated system Entropy (S total ) increases i.e. Changes / evolutions occur  S Life 0  S total =  S Life +  S other >0 H C N O C H..

i.e.  S total >0 for an isolated system Entropy (S total ) increases i.e. Changes / evolutions occur  S reaction 0  S total =  S reaction +  S other >0 A(l)B(l) A(l) + B(l) C(s)

path S total S total (1) S total (2)  S total S total (max) dS total >0 dS total = 0 Changes / evolutions occur Equilibrium: Changes / evolutions DO not occur G system  S total path  G system  -  S total  G system G system (2) G system (1) dG system <0 Changes / evolutions occur G system (min) dG system = 0 Equilibrium: Changes/evolutions DO not occur

Equilibrium ? Inequilibrium ?

A B A + B C + D [D][C] [A][B] = K ? Chemistry slow in space/ ISM...inequilibrium conditions

A + B C + D Path Energy, E A + B C + D EaEa T Equilibrium

A + B C + D Path Energy, E A + B C + D EaEa T Inequilibrium Equilibrium

Path Orka, E EaEa T HNC HCNExample: HNC HCN Equilibrium [HCN] [HNC]  10 5

HNC HCN Path Energy, E HNC HCN EaEa T Dæmi: Inequilibrium in ISM: [HCN] [HNC]  1

Equilibrium: [HCN] [HNC]  10 5 Inequilibrium in ISM: [HCN] [HNC]  1 HNC HCN ;  G = 0 ;  G < 0  G =  G o + RT ln( ) [HCN] [HNC]  G o = - RT ln(K)  G  - 3 J mol -1  G < - 3 J mol -1 = maximum work!?  G Reaction occurs “to right”: HNC HCN

 G = maximum work!? HNC HCN w = work  G = w max reagents Products w = work q = heat  U = Internal energy = w 1 + q 1 = w 2 + q 2 = w 3 + q 3 : = w max + q min :  G = w reversible