Where Chemistry Can Take You

Where Chemistry Can Take You

From the Lab to the Stars

From Utah to China, Japan & Switzerland

by Terry A. Ring, Ph. D.

Engineering Scholars

Earning a Living with EngineeringTalk about some of my research

Making Powders by Crystallization[= Precipitation]

NucleationCrystal Growth

Making Nano ParticlesNano Particles = Big Surprises

Ring’s Chemistry Competition

What do you want to be when you grow up?

Many possibilities to use your scientific education! Biologist Chemist Physicist Engineer – Different Flavors

YOUR DECISION HAS CONSEQUENCES! $$$$$$

How Much Do You Want to Earn When You Grow up?

Job GrowthAll Engineering Job Growth rate is

~19%/yr

Do the Popular Professions Pay Well?

Which Job Pays More?

Computer Engineer?Biologist?Chemist?Chemical Engineer?

Salary Information Chem. Eng.

Median Salary for B.S. ChE =$62,000/yr

Starting Salary

Chemical Engineering Professions

PetroChemical IndustryElectronics Industry

Chip ProcessingPharmaceuticals Industry

BioProcessingLawyers (Patents)Medical Doctors

Crystalization Research

Additives Control of Particle Shape

Epitaxial Aggregation

Mixing - 1μs to 10 ms

Nucleation - 10μs or mixing time

Growth - 10μs or mixing time

Aggregation - 10 msSelf Assembly - 10 ms

Hexagonal Packing of Spheres

Light Diffraction

Defects in Ordered Arrays Bend Light

Optical Semiconductors

Photonic Crystal Light Pipe

Light PipeLight Leaving Pipe

High Temperature SuperConductor

Time

Models of Crystallizer

Energy Dissipation Rate W/kg

Preventing Crystallization

-20

0

20

40

60

0 50 100 150 200 250 300 350Time (min)

Tem

pera

ture

(C

)

Bath Sample

Freezing pointSamples cooled at 20 C/hour between 30 C and -15 C

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7-100

-80

-60

-40

-20

0

20

40

Tem

pera

ture

( C

)

Liquid

Equilibrium Solubility

Surface NucleationTemperature

Homogeneous NucleationTemperature

LiBr•3H2Osolid

LiBr•2H2Osolid

LiBr Weight Fraction

Effect of Additives

0 10 20 30 40 50 60 70 80 90-40

-30

-20

-10

0

10

20

Cry

stall

iza

tio

n T

emp

era

ture

(ºC

)

Equilibrium FreezingPoint

No additive,LiBr.2H2Ocrystals

500 ppmUramil

Surface Energy of Crystal/Solution Interface (erg/cm2)

Formaldehyde Sensor

Silver LeadWires

Surface Electrodes:Fired-On

Silver PasteDoped

Nickel OxideThin Film

Alumina Substrate

3 mm

1 mm 1 mm

2.5 mm 2.5 mm

10 mm

0.5 umFilm

Thickness

2 mm

Micro-Weld

+-

Nano-sized Cluster Nucleation

IntroductionClassical Nucleation Theory & LimitationsNew Theory & Findings

Terry A. RingChemical EngineeringUniversity of Utah

The Nanoscale is small!Conventional Machines (m - mm)

Microelectronics (micron = 10-6 m) (10 cm down to 0.1 µm)

Nanotechnology nanometer= 10-9 m (100 nm to 1 nm)

Introduction

Unique Properties of Nanosized Particles Plasmon Resonance -color due to size, color change due

to adsorption-sensors Between Bulk and Atomic Electrical Properties Catalytic Properties

Magic Cluster Sizes C60, C70, C nanotubes, Na clusters of 8, 20, 40, 58 and 92

Silicon Particles

Stimulated Emission CdS Nano-Clusters-Laser

Lasing only when quantum dot concentration is sufficiently high.

Stimulated emission>Auger recombination

Klimov, V. Mikhailovsky, A.,Xu, S., Hollingswork, J., Malko, A., Bawendi, M., Eiser, H-J., Leatherhead, C.A.

Science 290,314 (2000) Science 287,1011 (2000)

Fullerene Synthesis

Not Predicted By Theory!

Nanoparticle Synthesis = Nucleation

• Classical Nucleation Theory vs New Theory– Binding Energy per Li atom

Kouteckky, J. and Fantucci, P., Chem. Rev., 86,539-87(1986).

0 10 20

18.3358

-0

( )GSis

....4 a12

.kB T

ig

2

3 1

ig

.0 ig

201 ,is ig

G(i) = - i kBT lnS + a ao2i2/3

Population Balances

Classical Nucleation = single atom addition

ij=(i+j), Population Balance

- Multi-atom Addition

ij=(i+j)exp(-Gij/kBT),i

ikikiki

k

iikik CCCCtC

1,

1

1,2/1/

1,1111,12

1/ CCCCtC kkkkk

Quantum Mech. Classical

0 1 106

2 1063 10

60

0.5

1

C,m 1

N( ),.m t 1

C,m 2

N( ),.m t 2

.m t0 0.05 0.1

0

0.5

1

C,m 1

N( ),.m t 1

C,m 2

N( ),.m t 2

.m t

0 1 2 3 4 5 6 7 8 910

0.9999

4.63056e-33

N ,.tmax

2t k

C,

tmax

2k

N( ),.tmax t k

C,tmax k

9k0 1 2 3 4 5 6 7 8 910

1 1014

1 1013

1 1012

1 1011

1 1010

1 109

1 108

1 107

1 106

1 105

1 104

0.0010.01

0.11

,.tmax

2t k

,tmax

2k

( ),.tmax t k

,tmax k

1

k

Population Comparison

New Theory of Nucleation

Overcomes Limitations of Classical Nucleation Theory Multi-atom addition Free Energy driving force for Diffusion

and Addition Predicts Transients for Cluster

Concentration of Each SizeQualitative similar to Si Plasma Expts

Collision Energetics

0 2 40

0.2

0.4

0.6

0.8

Collision Trajectory, R/re

BE

/ n

(eV

)

BE (i+j)

o

BE j

o BE i

o

+

BE j

BE i

+* *

²E

EACrystallo- luminescence

Figure 3 Collision trajectory for collision between i=3 and j=4 clusters,showing ground state energies before and after collision, as well as theactiviation energy of collsion.

Crystalloluminesent Spectrum

Intensity vs Energy Intensity =

collisions/per unit time = photons/unit time

Wavelength E = hc/l

Human eye detection @ 3x104photons/cm2/s at λ 510 nm

0 0.5 1 1.5 2 2.51 10

141 10

131 10

121 10

111 10

101 10

91 10

81 10

71 10

61 10

51 10

40.001

0.01

0.1

I,i k

E,i k

eV

Similar to Line Spectra

Crystalloluminescence• Term Schoenwald in 1786

30 References 1786 and 1957 • “An understanding of crystalloluminescence in not to satisfactory at the present

time,” E.N. Harvey 1957

Examples: NaCl, KCl, NaF, AsCl3, K2SO4, As3O3, Sr(NO3)2,, CoSO4, K2CO3, KHSO3, NaKSO4, NaKCrO4, NaKSeO4,

Na2SO4, benzoic acid, and ice, water.

16 References 1957-1991 (15 Russian+ 1 UK + 1 Italian Review)

“It is not possible to … provide either a unifying physical picture of the microscopic mechanism governing

(crystalloluminescence) or a physical rule that allows (identification of) conditions...where the phenomenon is stronger,”

Barsanti, M. & Maccarrone,,F., 1991

3 References from 1991-2000 (2 India, 1 Russian)

Experimental Observations

Delay time is a function of concentration & mixing

Flashes are Short < 80 ns

Peak Count rates ~5-8x105 photons/s

Temporal & Spatial Bunching of Flashes

340nm<λ<380 nmBlue White Light

Gibbon, M.A., Sopp, H. , Swanson, J., and Walton, A.J., J. Phys. C. 21,1921(1988).

Saturated NaCl + Conc. HCl - 120 s observation time

Spectra Has Series of Peaks

Different from Thermal

Luminescence Photoluminescence Impurities in Crystal

have a Big Effect Spectrum

Rabinerson, A.I. Wladimirskaya, M.A., Acta Physicochimica URSS, 10,859(1939)

Makes New Predictions

Explains the reason for the occurrence of Magic Clusters and how the change with time.

Method to Quantitatively Measure Nucleation Events

Predicts Crystalloluminescent SpectrumWhere could we see Crystalloluminescence?

H2O Condensation Nucleation Interstellar Dust Nucleation Light from Deep Sea Vents

Water Condensation due to Shock Wave

Interstellar Dust Clouds - Light from the Fringe - Crystalloluminescence due to Nanocluster Nucleation

Nanocluster, Ti14C13 with emission peak at 20.1 microns is seen in Egg Nebula byA.G.G.M. Thielens and M.A. DuncanScience 288,313(2000)

this joins some 120 other small molecules identified in the vicinity of stars, interstellar gas and dust clouds

Experimental Verification

Super Novae

Deep Sea Vents

C&E News 12/21/98National Geographic October 2000

Deep Sea Life

Salt Lake Tribune, 2/13/97National Geographic October 2000

Deep Sea Vents

Deep Sea Vents Spew Solublized Salts into the cold sea, causing Precipitation & Crystalloluminescence

In the Deep Ocean, Deep Sea Vents are the only source of Chemical Energy and Food

Mobile Animals need to be able to locate these Vents to eat - so they need eyes!! EAT AT JOE’S

Once in a while you get shown the light…..

In the strangest places… If you look at it right.